CA1106974A - Method and apparatus for remote display of analog signals occurring in computer controlled machine tools - Google Patents
Method and apparatus for remote display of analog signals occurring in computer controlled machine toolsInfo
- Publication number
- CA1106974A CA1106974A CA295,646A CA295646A CA1106974A CA 1106974 A CA1106974 A CA 1106974A CA 295646 A CA295646 A CA 295646A CA 1106974 A CA1106974 A CA 1106974A
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- CA
- Canada
- Prior art keywords
- digital
- analog
- memory
- sequence
- analog signal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/418—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS], computer integrated manufacturing [CIM]
- G05B19/4181—Total factory control, i.e. centrally controlling a plurality of machines, e.g. direct or distributed numerical control [DNC], flexible manufacturing systems [FMS], integrated manufacturing systems [IMS], computer integrated manufacturing [CIM] characterised by direct numerical control [DNC]
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B19/00—Programme-control systems
- G05B19/02—Programme-control systems electric
- G05B19/18—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form
- G05B19/406—Numerical control [NC], i.e. automatically operating machines, in particular machine tools, e.g. in a manufacturing environment, so as to execute positioning, movement or co-ordinated operations by means of programme data in numerical form characterised by monitoring or safety
- G05B19/4063—Monitoring general control system
-
- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B2219/00—Program-control systems
- G05B2219/30—Nc systems
- G05B2219/50—Machine tool, machine tool null till machine tool work handling
- G05B2219/50185—Monitoring, detect failures, control of efficiency of machine, tool life
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
Abstract
ABSTRACT OF THE DISCLOSURE
An analog signal which occurs in a computer controlled machine tool is converted to digital form at the machine tool site and is stored in a memory portion of the machine tool com-puter. The digitized analog signal is subsequently read out of the memory and is transmitted to a remote diagnostic unit via a conventional digital transmission link. The digitized analog signal received by the diagnostic unit is stored in a memory portion of the diagnostic computer and is subsequently read out and converted back to analog form for display on an oscilloscope in the diagnostic unit to aid in the diagnosis of existing or incipient faults in the machine tool.
An analog signal which occurs in a computer controlled machine tool is converted to digital form at the machine tool site and is stored in a memory portion of the machine tool com-puter. The digitized analog signal is subsequently read out of the memory and is transmitted to a remote diagnostic unit via a conventional digital transmission link. The digitized analog signal received by the diagnostic unit is stored in a memory portion of the diagnostic computer and is subsequently read out and converted back to analog form for display on an oscilloscope in the diagnostic unit to aid in the diagnosis of existing or incipient faults in the machine tool.
Description
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This invention relates to diagnostic circuits for computer controlled machine tools or the likeO
In the past, a diagnostic communication system has been designed which interlinks any one of a number of geographically separated, computer controlled machine tools with diagnostic and analysis equipment in a central diagnostic unit which is remote from the machine toolsO
This diagnostic communication system i5 described in UOS.
Patent No. 3,882,305, granted on May 6, 19750 In this system, the computer associated with any selected machine tool is connected with the diagnostic apparatus over a telephone line, and the machine tool is caused to execute a predete~mined diagnostic routine in response to instruc-tions transmitted to the machine tool computer from the diagnostic apparatus. The operating characteristics of the machine tool are monitored during the operation there-of and are communicated to the diagnostic apparatus9 where they are compared with corresponding characteristics pre-viously collected for the same machine tool, and with de-sign limit parametersO Such comparisons enable an analyst at the remote diagnostic site to diagnose actual or in-cipient faults ip the machine tool.
The above-described diagnostic communication system has one major shortcoming in that it is limited to monitoring machine tool characteristics which are ex-pressed as digital signals and has no provision for moni-toring analog signals, although there are analog signals in the machine tool which in some cases are more reveal-ing in regard to faults than are the digital signalsO
Accordingly, the present invention provides a method and apparatus for transmitting analog signals from a computer controlled machine tool to an analog display device in a remote location and for displaying the analog signals to aid in the diagnosis of existing or incipient faults in the machine tool.
In particular, the present invention provides a method of displaying an analog signal which occurs in a computer controlled machine tool circuit on an analog display device which is located in a site remote from the machine tool site, including the steps of: converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corresponding time, said conver sion being performed at the machine tool site, transmit-ting said sequence of digital signals to said remote site, converting said sequence of digital signals into an approximation of said analog signal at said remote site, and applying said analog signal approximation to said analog display device to display said analog signal ap-proximation thereon.
The invention also provides apparatus for dis-playing an analog signal which occurs in a computer con-trolled machine tool circuit on an analog display device which is located in a site remote from the machine tool site, said apparatus comprising probe means for picking up the desired analog signal in-said machine tool circuit, an analog to digital converter coupled to the output of said probe means for converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corre-sponding time, means for transmitting said sequence of digital signals to said remote site, means at said remote site for receiving said transmitted sequence of digital signals, a digital to analog converter at said remote site for converting said sequence of digital signals into an approximation of said analog signal, and analog dis-play means coupled to the output of said digital to analog converter for displaying said approximation of said analog signal.
A preferred embodiment of the invention will now be described with reference to the accompanying draw-ings, wherein:
Figure 1 is a general block diagram of the pre-ferred embodiment of the invention;
Figure 2 is a detailed block diagram of the analog to digital converter and controller 10 shown in Figure l;
Figure 3 is a detailed block diagram of the analog to digital control circuit 38 shown in Figure 2;
Figure 4 is a detailed block diagram of the digital to analog converter and controller 22 shown in Figure l;
Figure 5 is a schematic circuit diagram of the output circuit for one of the digital to analog convert-ers 74 and 76 shown in Figure 4; and Figure 6 is a set of waveforms illustrating the operation of the embodiment shown in Figures 1 to 5.
Referring to Figure 1, the preferred apparatus of the invention includes an analog to digital converter and controller 10, a local memory 12J which is preferably 7~L
a part of a machine tool computer 13 but which may be separate therefromJ a digital transmission system includ-ing a local modem 14~ a communication link such as tele-phone lines 16, and a remote modem 18J which is prefer-ably a part of a diagnostic communication system such as disclosed in the above-noted U.S. Patent No. 3,882~305 but which may be separate therefrom. It will be under-stood that a radio transmission link could be used in place of the telephone transmission link if desired. The apparatus further includes a remote memory 20, which is preferably but not necessarily a part of a diagnostic computer 21, a digital to analog converter and controller 22J and an analog display device 24.
In the method of this invention, the desired analog signal, and possibly a timing signal therefor, is picked up in the machine tool circuitry by a manual probe 26 (Figure 2) which is coupled to the input of analog to digital converter and controller 10. This analog signal is converted in A/D converter and controller 10 to a se-quence of digital signals each of which represent the am-plitude of the analog signal at a corresponding time.
This sequence of digital signals is applied to local mem-ory 12 where it is stored. At some subsequent time, the sequence of digital signals is read out of memory 12 and is transmitted via local modem 14, telephone lines 16, and remote modem 18 to remote memory 20. The sequence of digital signals stored in remote memory 20 is subsequent-ly read out and is applied to digital to analog converter and controller 22 where it is converted back to analog form as an approximation of the original analog signal.
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The output of D/A converter and controller 22 is applied to analog display device 24 for display thereonO
Telephone handsets 28 and 30 are preferably provided at the machine tool and diagnostic sites, respec-tively, for voice communication between the analyst at the diagnostic site and the machine tool operator. The analyst usually verbally specifies the desired analog signal and timing signal to the machine tool operator who then connects test probe 26 to the appropriate test points in the machine tool circuitry. When the probe is connect-ed, the signal conversion, transmission, reconversion, and display are initiated by the analyst at the remote diagnostic site.
Figu~es 2 and 3 show a detailed block diagram of analog to digital converter and controller 10. Refer~
ring to Figure 2, the analog input signal from manual probe 26 is applied to a conventional analog to digital converter 32 which also receives clock pulse inputs from a clock counter and register circuit 34 which is driven by an oscillator 36. Clock counter and register 34 re-ceives a digital input number which preloads the counter to determine the clock period to be used for the analog to digital conversion. The clock period input number, which is preloaded into clock counter 34, determines the number of oscillator input pulses required to make the clock counter overflow. Any desired number of input pulses from 1 to the capacity of counter 34 can be se-lected as the clock timing period. The clock counter overflow signal forms the clock pulses for the systemO
The clock period input number is stored in a conventional register and is reloaded into the clock counter every time it overflows so that each clock period is equal to the selected clock period.
Analog to digital converter 32 performs an A/D
conversion cycle every time it receives a clock pulse.
During the A/D conversion cycle, A/D converter 32 produces a positive STATUS output signal which goes to zero when the conversion cycle is completed. The STATUS signal and SIGN (+/-) signal of the analog quantity digitized in the preceding conversion cycle are applied to an A/D control circuit 38 which is disclosed in detail in Figure 3 and which is described hereinafter.
When the appropriate timing signal is received or generated, A/D control circuit 38 generates a DMA
(Direct Memory Access) REQUEST signal which is applied to machine tool computer 13 and causes the digital output of A/D converter 32 to be entered in local memory 12 at the address specified by an address counter 40. Address counter 40 is preset by a digital input number which specifies the initial address for the first digital word of the A/D conversion process. Thereafter, address counter 40 is incremented by a TSC signal from local com-puter 13 which goes high at the end of each entry of digital data into local memory 12 so that successive out-puts of A/D converter 32 are stored in sequence in local memory 12. The TSC signal also decrements a word counter 42 which is preloaded with a digital input number which specifies the total number of words that are to be stored in the sequence of digital signals which appear at the output of A/D counter 32.
When the selected number of digital words have been stored in local memory 12, word counter 42 returns to zero and produces a DONE signal which is applied to A/D
control circuit 38 and terminates the entry of data into local memory 12. (It should be noted that A/D converter 32 continues to operate after the DONE signal is generat-ed, but its digital output signals are not entered in local memory 12).
At the start of the above-described A/D conver- !
sion process, the digital data specifying the desired clock period, the desired A/D sample length, and the ini-tial address of the A/D sample are applied to counters 34, 42 and 40, respectively, from machine tool computer 13 or ~rom manual input devices (not shown) or from diagnostic computer 21. An EXT/INT TIMING signal, which selects either internal or external timing, and a TRIG +/- signal, which selects a positive going or negative going trigger, are applied to A/D control circuit 38 from the same source.
An ARM signal, which initiates the A/D conversion process, and DMA STATE signal, which is high during the A/D con-version process and goes low when DONE goes high, are also applied from machine tool computer 13 to A/D control circuit 38. The ARM and DMA STATE signals could also be generated by diagnostic computer 21 or by other suitable control circuits in other embodiments of the inventionD
A TRIG ENABLE input is also provided to A/D control cir-cuit 38 for use when no external or internal trigger is provided as described hereinafter.
Figure 3 shows the individual circuit elements in A/D control circuit 38. The output of this circuit is 7~ .
the DMA REQUEST signal which is the inverted output o~ a NAND gate 44 which receives inputs from a single shot multivibrator 46, a flip-flop 48, and a non-inverting amplifier 50. The output of gate 44 goes low when all of the inputs to NAND gate 44 go high, and this causes DMA
REQUEST to go high. The operation of this circuit will be explained starting with the receipt of an ARM signal at the input to noninverting amplifier 50. The ARM signal is low between A/D conversion cycles and goes high to lni-tiate a conversion cycle. When the ARM signal goes high,it resets flip-flop 48 through NAND gate 62 if the DMA
STATE signal is low, which it is between conversion cycles This disables gate 44 until flip-flop 48 is set by the circuit described below.
At the end of an A/D conversion cycle in A/D
converter 32, the STATUS signal goes from high to low, which triggers single shot multivibrator 46 and flip-flop 52 through inverting amplifier 66. The output of single shot multivibrator 46 is applied to one input of AND gate 20 47 which also receives a DONE signal input from inverting amplifier 49. AND gate 47 is enabled during the conver sion process but is disabled to terminate the entry of data into the memory when the DONE signal goes high, which occurs when word counter 42 reaches zero at the end of the conversion process.
Under the proper conditions, described below, the triggering of flip-flop 52 may clock flip-~lop 48 through gates 54, 56, and 58 and thus enable gate 44 and generate the DMA REQUEST signalO In the case where flip-30 flop 52 clocks flip-flop 48, the polarity of the signal _9 _ 37~
causing the clocking is determined ~ointly by the SIGN
(+/ ) input to flip-flop 52, which changes with the sign of the analog input to A/D converter 32, and the TRIG -/+
selection signal input to exclusive OR gate 58, which acts as a switchable inverter. The foregoing triggering se-quence is followed when the EXT/INT TIMING signal is low which selects internal timing triggered by flip-flop 520 When external timing is selected, the EXT/INT
TIMING signal is high and flip-flop 48 is cl~cked by an external timing signal applied to one input of NAND gate 60, whose output is applied to one input of NAND gate 560 The polarity of this trigger is also controlled by the TRIG -/+ signal through exclusive OR gate 58. Thus either internal triggering controlled by NAND gate 54 or external triggering controlled by NAND gate 60 can be se-lected, with the polarity of either trigger being select-ed by the TRIG -/+ signal. In cases where neither exter-nal nor internal triggering is available or desiredJ
flip-flop 48 can be triggered directly by a TRIG ENABLE
20 signal applied to the set input of flip-flop 48 through a non-inverting amplifier 64.
In the above-described manner, the DMA REQUEST
signal is switched to its high state by NAND gate 44 after each analog to digital conversion cycle of A/D converter 32 after the ARM signal goes high until the DONE signal from word counter 42 goes high and disables AND gate 47.
This disables NAND gate 44 and terminates the entry of the output of D/A converter 3~ into local memory 12~ The DONE signal goes high when word counter 42J which was pre-30 set to the desired total number of digital numbers in the ~L~.r~`6~7~.
A/D samplel returns to zero signifying that the desirednumber of digital numbers have been entered ln local mem-ory 12.
An example of the above-described A/D conversion cycle is illustrated in the wave forms of Figure 60 Wave-form 6(C) is a single wave rectified voltage which is switched on at a variable phase angle by a silicon con-trolled rectifier (not shown) in the machine tool control circuit and is used as an example of the type of analog signals which are generated within the machine tool con-trol circuits and which can be displayed remotely with the method and means of this invention. Waveform 6(B) is a timing pulse in the machine tool control circu~t which initiates the firing of the silicon controlled rectifier whose conduction generates waveform 6(C). Each of the sliced, single wave rectified waveforms, shown in wave-form 6(C), commences after a fixed time delay T1 from the timing pulse 6(B) which initiates it. Time delay Tl is determined by the circuit characteristics of the machine tool control circuit. In this example, the trailing, negative going edge of trigger pulses 6(B) are used as the trigger but it is also possible to use the leading, positive going edge as a trigger, and in this case, time delay Tl would be measured from the leading edge of the corresponding trigger pulse 6(B).
In this example, analog signal 6(C) and external timing signal 6(B) are picked up by probe 26 in the machine tool circuitry. The EXT/INT TIMING signal is switched high to select external timingO The TRIG -/+
signal is switched high to select triggering on the nega-7~L .
tive going transition. The digital numbers which select the clock period, the A/D sample length, and the initial address are selected and applied to their respective counters 34, 42, and 40. After these preliminary steps had been taken, the analyst in the remote diagnostic site causes the ARM signal to be generated which initiates the A/D conversion process.
As shown in waveform 6(A), the first clock pulse that occurs after the trailing edge o~ the next timing signal 6(B) cause the digital number resulting from the corresponding A/D conversion to be stored in local memory 12 at the address specified in address counter 40. The first clock pulse after the trailing edge of timing pulse 6(B) occurs at a time delay T2 which could be any value from zero to the length of one time clock period T3. At each of the numbered steps on wave-form 6(A), the corresponding analog signal 6(C) is digit-ized, i.e., a digital number corresponding to the instan-taneous amplitude of the analog signal is generated by A/D converter 32. Each of the steps 1--- Nl is separated by a clock pulse interval T3 corresponding to the size of the clock period digital number entered into the clock counter and register circuit 34. The A/D conversion process continues up to the word number Nl, which is the total sample length input number entered into word counter 42 and indicates the desired length of the analog sample, i.e., the total number of digital numbers entered in local memory 12. In this particular example, the sample length Nl is selected to cover a single cycle of the analog waveform 6(C), but if desired, a larger sample 7~
length N2 could be selected to cover two cycles of wave-form 6(C)o Any length sample up to the limits of count-ers 34 and 42 can be selected.
At the end of the selected sample length Nl or N2, word counter 42 returns to zero and generates the DONE signal which terminates the A/D conversion process and which may initiate transmission of the digitized analog signal stored in local memory 12 during the pre-ceding A/D conversion process. Alternately, the digit-ized analog signal, which comprises a sequence of digitalnumbers each of which represents the amplitude of the analog signal at a corresponding time, such as illustrat-ed in Figure 6(C) by the amplitudes A3 and A6, could be transmitted over the DCS transmission link at any de-sired time by conventional transmission circuits and stored in remote memory 20 for subsequent display on analog display device 24.
The digital to analog converter and controller 22 is shown in detailed block diagram form in Figure 40 In this particular example, analog display device 24 is an oscilloscope and two digital to analog converters 74 and 76 are employed, one for the vertical deflection voltage of the oscilloscope and the other for the hor-izontal deflection voltage. The digitized analog signal stored in remote memory 20 is applied to D/A converter 74 to generate an approximation of analog waveform 6(C) while a horizontal sweep voltage, which, in this case, is also stored as a sequence of digital signals in remote memory 20, is applied to D/A converter 76 to generate a horizontal deflection voltage. The output voltages of ~p~
both D/A converters 74 and 76 are amplified by correspond-ing amplifiers 78 and 800 The digital numbers for the horizontal and ver-tical deflection signals are interleaved in time sequence, i.eO, first a horizontal number is applied to the data in-put bus 82, then a vertical numberJ then the next hori-zontal number, followed by the next vertical number, and so on in interleaved time sequence. Each of these numbers is gated in parallel through data gates 84 to two sets of data latches 86 and 88 which are coupled respectively to D/A converters 74 and 76 and apply the input voltages thereto. Every time one of the digital words is applied to data input bus 82, and gated to data latches 86 and 88 by a DATA GATE signal, a channel select word is applied to a channel decoder 90 which enables either NAND gate 92 or NAND gate 94 depending on whether the digital number on data input bus 82 is a vertical deflection number or a horizontal deflection number. A timing signal TP, which is applied in parallel to NAND gates 92 and 94, clocks the data into the corresponding data latches 86 or 88, while the other data latches 86 or 88 retain their pre-vious data. In this manner, the interleaved vertical and horizontal data input numbers applied to data input bus 82 are routed to the correct D/A converter.
In some cases, auxiliary circuits 96 are em-ployed, which may be a strip recorder, X-Y plotter, dig-ital printout, or the like, and in these cases, separate channel select words may be provided to turn these de-vices on and off or to adjust their operating parameters.
The output of both D/A converters 74 and 76 are 6~74 good approximakions of the analog voltages from which their respective digital input signals are derived. The degree of approximation can be improved if desired by de-creasing the timing period T3 (Figure 6)o Figure 5 shows the preferred circuit for D/A
output amplifiers 78 and 80. The analog output signal from the corresponding D/A converter is applied to the negative input of a conventional operational amplifier 98 whose positive input is grounded and which has a feedback resistor 100 connected between its negative input and out-put to provide a parallel-parallel feedback which pro-duces a voltage at the output proportional to input cur-rent. The output of operational amplifier 98 is applied through resistor 102 to the negative input of a conven-tipnal operational amplifier 104 whose positive input is grounded. Feedback resistors 106 and 108 are connected in series between the output of operational amplifier 104 and the negative input thereof. Resistor 106 is variable and serves to adjust the gain of the amplifier. An off-set voltage is applied to the negative input terminal ofoperational amplifier 104 through an adjustable resistor 110 which adjusts the zero point for the analog function.
This circuit can be used for both vertical amplifier 78 and horizontal amplifier 80.
The above-described examples have utilized an external timing signal. In cases where no external tim-ing signal is available, internal timing can be used in which the analog to digital conversion process is initi-ated when the analog signal goes from a negative to a positive value or from a positive to a negati~e value as determined by the TRIG -/+ selection signal. When the selected analog signal does not normally change polarity, it can be offset half way from zero by conventional off-set circuit means at the input to A/D converter 32 so that there wiil be a shift of polarity at the start of the waveform for triggering purposes.
Although the illustrative embodiment of the in-vention has been described in considerable detail for the purpose of fully disclosing a practical operative struc-lC ture incorporating the invention, it is to be understood that the particular apparatus shown and described is in-tended to be illustrative only and that the various novel features of the invention may be incorporated in other structural forms without departing from the spirit and scope of the invention as defined in the subjoined claims.
This invention relates to diagnostic circuits for computer controlled machine tools or the likeO
In the past, a diagnostic communication system has been designed which interlinks any one of a number of geographically separated, computer controlled machine tools with diagnostic and analysis equipment in a central diagnostic unit which is remote from the machine toolsO
This diagnostic communication system i5 described in UOS.
Patent No. 3,882,305, granted on May 6, 19750 In this system, the computer associated with any selected machine tool is connected with the diagnostic apparatus over a telephone line, and the machine tool is caused to execute a predete~mined diagnostic routine in response to instruc-tions transmitted to the machine tool computer from the diagnostic apparatus. The operating characteristics of the machine tool are monitored during the operation there-of and are communicated to the diagnostic apparatus9 where they are compared with corresponding characteristics pre-viously collected for the same machine tool, and with de-sign limit parametersO Such comparisons enable an analyst at the remote diagnostic site to diagnose actual or in-cipient faults ip the machine tool.
The above-described diagnostic communication system has one major shortcoming in that it is limited to monitoring machine tool characteristics which are ex-pressed as digital signals and has no provision for moni-toring analog signals, although there are analog signals in the machine tool which in some cases are more reveal-ing in regard to faults than are the digital signalsO
Accordingly, the present invention provides a method and apparatus for transmitting analog signals from a computer controlled machine tool to an analog display device in a remote location and for displaying the analog signals to aid in the diagnosis of existing or incipient faults in the machine tool.
In particular, the present invention provides a method of displaying an analog signal which occurs in a computer controlled machine tool circuit on an analog display device which is located in a site remote from the machine tool site, including the steps of: converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corresponding time, said conver sion being performed at the machine tool site, transmit-ting said sequence of digital signals to said remote site, converting said sequence of digital signals into an approximation of said analog signal at said remote site, and applying said analog signal approximation to said analog display device to display said analog signal ap-proximation thereon.
The invention also provides apparatus for dis-playing an analog signal which occurs in a computer con-trolled machine tool circuit on an analog display device which is located in a site remote from the machine tool site, said apparatus comprising probe means for picking up the desired analog signal in-said machine tool circuit, an analog to digital converter coupled to the output of said probe means for converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corre-sponding time, means for transmitting said sequence of digital signals to said remote site, means at said remote site for receiving said transmitted sequence of digital signals, a digital to analog converter at said remote site for converting said sequence of digital signals into an approximation of said analog signal, and analog dis-play means coupled to the output of said digital to analog converter for displaying said approximation of said analog signal.
A preferred embodiment of the invention will now be described with reference to the accompanying draw-ings, wherein:
Figure 1 is a general block diagram of the pre-ferred embodiment of the invention;
Figure 2 is a detailed block diagram of the analog to digital converter and controller 10 shown in Figure l;
Figure 3 is a detailed block diagram of the analog to digital control circuit 38 shown in Figure 2;
Figure 4 is a detailed block diagram of the digital to analog converter and controller 22 shown in Figure l;
Figure 5 is a schematic circuit diagram of the output circuit for one of the digital to analog convert-ers 74 and 76 shown in Figure 4; and Figure 6 is a set of waveforms illustrating the operation of the embodiment shown in Figures 1 to 5.
Referring to Figure 1, the preferred apparatus of the invention includes an analog to digital converter and controller 10, a local memory 12J which is preferably 7~L
a part of a machine tool computer 13 but which may be separate therefromJ a digital transmission system includ-ing a local modem 14~ a communication link such as tele-phone lines 16, and a remote modem 18J which is prefer-ably a part of a diagnostic communication system such as disclosed in the above-noted U.S. Patent No. 3,882~305 but which may be separate therefrom. It will be under-stood that a radio transmission link could be used in place of the telephone transmission link if desired. The apparatus further includes a remote memory 20, which is preferably but not necessarily a part of a diagnostic computer 21, a digital to analog converter and controller 22J and an analog display device 24.
In the method of this invention, the desired analog signal, and possibly a timing signal therefor, is picked up in the machine tool circuitry by a manual probe 26 (Figure 2) which is coupled to the input of analog to digital converter and controller 10. This analog signal is converted in A/D converter and controller 10 to a se-quence of digital signals each of which represent the am-plitude of the analog signal at a corresponding time.
This sequence of digital signals is applied to local mem-ory 12 where it is stored. At some subsequent time, the sequence of digital signals is read out of memory 12 and is transmitted via local modem 14, telephone lines 16, and remote modem 18 to remote memory 20. The sequence of digital signals stored in remote memory 20 is subsequent-ly read out and is applied to digital to analog converter and controller 22 where it is converted back to analog form as an approximation of the original analog signal.
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The output of D/A converter and controller 22 is applied to analog display device 24 for display thereonO
Telephone handsets 28 and 30 are preferably provided at the machine tool and diagnostic sites, respec-tively, for voice communication between the analyst at the diagnostic site and the machine tool operator. The analyst usually verbally specifies the desired analog signal and timing signal to the machine tool operator who then connects test probe 26 to the appropriate test points in the machine tool circuitry. When the probe is connect-ed, the signal conversion, transmission, reconversion, and display are initiated by the analyst at the remote diagnostic site.
Figu~es 2 and 3 show a detailed block diagram of analog to digital converter and controller 10. Refer~
ring to Figure 2, the analog input signal from manual probe 26 is applied to a conventional analog to digital converter 32 which also receives clock pulse inputs from a clock counter and register circuit 34 which is driven by an oscillator 36. Clock counter and register 34 re-ceives a digital input number which preloads the counter to determine the clock period to be used for the analog to digital conversion. The clock period input number, which is preloaded into clock counter 34, determines the number of oscillator input pulses required to make the clock counter overflow. Any desired number of input pulses from 1 to the capacity of counter 34 can be se-lected as the clock timing period. The clock counter overflow signal forms the clock pulses for the systemO
The clock period input number is stored in a conventional register and is reloaded into the clock counter every time it overflows so that each clock period is equal to the selected clock period.
Analog to digital converter 32 performs an A/D
conversion cycle every time it receives a clock pulse.
During the A/D conversion cycle, A/D converter 32 produces a positive STATUS output signal which goes to zero when the conversion cycle is completed. The STATUS signal and SIGN (+/-) signal of the analog quantity digitized in the preceding conversion cycle are applied to an A/D control circuit 38 which is disclosed in detail in Figure 3 and which is described hereinafter.
When the appropriate timing signal is received or generated, A/D control circuit 38 generates a DMA
(Direct Memory Access) REQUEST signal which is applied to machine tool computer 13 and causes the digital output of A/D converter 32 to be entered in local memory 12 at the address specified by an address counter 40. Address counter 40 is preset by a digital input number which specifies the initial address for the first digital word of the A/D conversion process. Thereafter, address counter 40 is incremented by a TSC signal from local com-puter 13 which goes high at the end of each entry of digital data into local memory 12 so that successive out-puts of A/D converter 32 are stored in sequence in local memory 12. The TSC signal also decrements a word counter 42 which is preloaded with a digital input number which specifies the total number of words that are to be stored in the sequence of digital signals which appear at the output of A/D counter 32.
When the selected number of digital words have been stored in local memory 12, word counter 42 returns to zero and produces a DONE signal which is applied to A/D
control circuit 38 and terminates the entry of data into local memory 12. (It should be noted that A/D converter 32 continues to operate after the DONE signal is generat-ed, but its digital output signals are not entered in local memory 12).
At the start of the above-described A/D conver- !
sion process, the digital data specifying the desired clock period, the desired A/D sample length, and the ini-tial address of the A/D sample are applied to counters 34, 42 and 40, respectively, from machine tool computer 13 or ~rom manual input devices (not shown) or from diagnostic computer 21. An EXT/INT TIMING signal, which selects either internal or external timing, and a TRIG +/- signal, which selects a positive going or negative going trigger, are applied to A/D control circuit 38 from the same source.
An ARM signal, which initiates the A/D conversion process, and DMA STATE signal, which is high during the A/D con-version process and goes low when DONE goes high, are also applied from machine tool computer 13 to A/D control circuit 38. The ARM and DMA STATE signals could also be generated by diagnostic computer 21 or by other suitable control circuits in other embodiments of the inventionD
A TRIG ENABLE input is also provided to A/D control cir-cuit 38 for use when no external or internal trigger is provided as described hereinafter.
Figure 3 shows the individual circuit elements in A/D control circuit 38. The output of this circuit is 7~ .
the DMA REQUEST signal which is the inverted output o~ a NAND gate 44 which receives inputs from a single shot multivibrator 46, a flip-flop 48, and a non-inverting amplifier 50. The output of gate 44 goes low when all of the inputs to NAND gate 44 go high, and this causes DMA
REQUEST to go high. The operation of this circuit will be explained starting with the receipt of an ARM signal at the input to noninverting amplifier 50. The ARM signal is low between A/D conversion cycles and goes high to lni-tiate a conversion cycle. When the ARM signal goes high,it resets flip-flop 48 through NAND gate 62 if the DMA
STATE signal is low, which it is between conversion cycles This disables gate 44 until flip-flop 48 is set by the circuit described below.
At the end of an A/D conversion cycle in A/D
converter 32, the STATUS signal goes from high to low, which triggers single shot multivibrator 46 and flip-flop 52 through inverting amplifier 66. The output of single shot multivibrator 46 is applied to one input of AND gate 20 47 which also receives a DONE signal input from inverting amplifier 49. AND gate 47 is enabled during the conver sion process but is disabled to terminate the entry of data into the memory when the DONE signal goes high, which occurs when word counter 42 reaches zero at the end of the conversion process.
Under the proper conditions, described below, the triggering of flip-flop 52 may clock flip-~lop 48 through gates 54, 56, and 58 and thus enable gate 44 and generate the DMA REQUEST signalO In the case where flip-30 flop 52 clocks flip-flop 48, the polarity of the signal _9 _ 37~
causing the clocking is determined ~ointly by the SIGN
(+/ ) input to flip-flop 52, which changes with the sign of the analog input to A/D converter 32, and the TRIG -/+
selection signal input to exclusive OR gate 58, which acts as a switchable inverter. The foregoing triggering se-quence is followed when the EXT/INT TIMING signal is low which selects internal timing triggered by flip-flop 520 When external timing is selected, the EXT/INT
TIMING signal is high and flip-flop 48 is cl~cked by an external timing signal applied to one input of NAND gate 60, whose output is applied to one input of NAND gate 560 The polarity of this trigger is also controlled by the TRIG -/+ signal through exclusive OR gate 58. Thus either internal triggering controlled by NAND gate 54 or external triggering controlled by NAND gate 60 can be se-lected, with the polarity of either trigger being select-ed by the TRIG -/+ signal. In cases where neither exter-nal nor internal triggering is available or desiredJ
flip-flop 48 can be triggered directly by a TRIG ENABLE
20 signal applied to the set input of flip-flop 48 through a non-inverting amplifier 64.
In the above-described manner, the DMA REQUEST
signal is switched to its high state by NAND gate 44 after each analog to digital conversion cycle of A/D converter 32 after the ARM signal goes high until the DONE signal from word counter 42 goes high and disables AND gate 47.
This disables NAND gate 44 and terminates the entry of the output of D/A converter 3~ into local memory 12~ The DONE signal goes high when word counter 42J which was pre-30 set to the desired total number of digital numbers in the ~L~.r~`6~7~.
A/D samplel returns to zero signifying that the desirednumber of digital numbers have been entered ln local mem-ory 12.
An example of the above-described A/D conversion cycle is illustrated in the wave forms of Figure 60 Wave-form 6(C) is a single wave rectified voltage which is switched on at a variable phase angle by a silicon con-trolled rectifier (not shown) in the machine tool control circuit and is used as an example of the type of analog signals which are generated within the machine tool con-trol circuits and which can be displayed remotely with the method and means of this invention. Waveform 6(B) is a timing pulse in the machine tool control circu~t which initiates the firing of the silicon controlled rectifier whose conduction generates waveform 6(C). Each of the sliced, single wave rectified waveforms, shown in wave-form 6(C), commences after a fixed time delay T1 from the timing pulse 6(B) which initiates it. Time delay Tl is determined by the circuit characteristics of the machine tool control circuit. In this example, the trailing, negative going edge of trigger pulses 6(B) are used as the trigger but it is also possible to use the leading, positive going edge as a trigger, and in this case, time delay Tl would be measured from the leading edge of the corresponding trigger pulse 6(B).
In this example, analog signal 6(C) and external timing signal 6(B) are picked up by probe 26 in the machine tool circuitry. The EXT/INT TIMING signal is switched high to select external timingO The TRIG -/+
signal is switched high to select triggering on the nega-7~L .
tive going transition. The digital numbers which select the clock period, the A/D sample length, and the initial address are selected and applied to their respective counters 34, 42, and 40. After these preliminary steps had been taken, the analyst in the remote diagnostic site causes the ARM signal to be generated which initiates the A/D conversion process.
As shown in waveform 6(A), the first clock pulse that occurs after the trailing edge o~ the next timing signal 6(B) cause the digital number resulting from the corresponding A/D conversion to be stored in local memory 12 at the address specified in address counter 40. The first clock pulse after the trailing edge of timing pulse 6(B) occurs at a time delay T2 which could be any value from zero to the length of one time clock period T3. At each of the numbered steps on wave-form 6(A), the corresponding analog signal 6(C) is digit-ized, i.e., a digital number corresponding to the instan-taneous amplitude of the analog signal is generated by A/D converter 32. Each of the steps 1--- Nl is separated by a clock pulse interval T3 corresponding to the size of the clock period digital number entered into the clock counter and register circuit 34. The A/D conversion process continues up to the word number Nl, which is the total sample length input number entered into word counter 42 and indicates the desired length of the analog sample, i.e., the total number of digital numbers entered in local memory 12. In this particular example, the sample length Nl is selected to cover a single cycle of the analog waveform 6(C), but if desired, a larger sample 7~
length N2 could be selected to cover two cycles of wave-form 6(C)o Any length sample up to the limits of count-ers 34 and 42 can be selected.
At the end of the selected sample length Nl or N2, word counter 42 returns to zero and generates the DONE signal which terminates the A/D conversion process and which may initiate transmission of the digitized analog signal stored in local memory 12 during the pre-ceding A/D conversion process. Alternately, the digit-ized analog signal, which comprises a sequence of digitalnumbers each of which represents the amplitude of the analog signal at a corresponding time, such as illustrat-ed in Figure 6(C) by the amplitudes A3 and A6, could be transmitted over the DCS transmission link at any de-sired time by conventional transmission circuits and stored in remote memory 20 for subsequent display on analog display device 24.
The digital to analog converter and controller 22 is shown in detailed block diagram form in Figure 40 In this particular example, analog display device 24 is an oscilloscope and two digital to analog converters 74 and 76 are employed, one for the vertical deflection voltage of the oscilloscope and the other for the hor-izontal deflection voltage. The digitized analog signal stored in remote memory 20 is applied to D/A converter 74 to generate an approximation of analog waveform 6(C) while a horizontal sweep voltage, which, in this case, is also stored as a sequence of digital signals in remote memory 20, is applied to D/A converter 76 to generate a horizontal deflection voltage. The output voltages of ~p~
both D/A converters 74 and 76 are amplified by correspond-ing amplifiers 78 and 800 The digital numbers for the horizontal and ver-tical deflection signals are interleaved in time sequence, i.eO, first a horizontal number is applied to the data in-put bus 82, then a vertical numberJ then the next hori-zontal number, followed by the next vertical number, and so on in interleaved time sequence. Each of these numbers is gated in parallel through data gates 84 to two sets of data latches 86 and 88 which are coupled respectively to D/A converters 74 and 76 and apply the input voltages thereto. Every time one of the digital words is applied to data input bus 82, and gated to data latches 86 and 88 by a DATA GATE signal, a channel select word is applied to a channel decoder 90 which enables either NAND gate 92 or NAND gate 94 depending on whether the digital number on data input bus 82 is a vertical deflection number or a horizontal deflection number. A timing signal TP, which is applied in parallel to NAND gates 92 and 94, clocks the data into the corresponding data latches 86 or 88, while the other data latches 86 or 88 retain their pre-vious data. In this manner, the interleaved vertical and horizontal data input numbers applied to data input bus 82 are routed to the correct D/A converter.
In some cases, auxiliary circuits 96 are em-ployed, which may be a strip recorder, X-Y plotter, dig-ital printout, or the like, and in these cases, separate channel select words may be provided to turn these de-vices on and off or to adjust their operating parameters.
The output of both D/A converters 74 and 76 are 6~74 good approximakions of the analog voltages from which their respective digital input signals are derived. The degree of approximation can be improved if desired by de-creasing the timing period T3 (Figure 6)o Figure 5 shows the preferred circuit for D/A
output amplifiers 78 and 80. The analog output signal from the corresponding D/A converter is applied to the negative input of a conventional operational amplifier 98 whose positive input is grounded and which has a feedback resistor 100 connected between its negative input and out-put to provide a parallel-parallel feedback which pro-duces a voltage at the output proportional to input cur-rent. The output of operational amplifier 98 is applied through resistor 102 to the negative input of a conven-tipnal operational amplifier 104 whose positive input is grounded. Feedback resistors 106 and 108 are connected in series between the output of operational amplifier 104 and the negative input thereof. Resistor 106 is variable and serves to adjust the gain of the amplifier. An off-set voltage is applied to the negative input terminal ofoperational amplifier 104 through an adjustable resistor 110 which adjusts the zero point for the analog function.
This circuit can be used for both vertical amplifier 78 and horizontal amplifier 80.
The above-described examples have utilized an external timing signal. In cases where no external tim-ing signal is available, internal timing can be used in which the analog to digital conversion process is initi-ated when the analog signal goes from a negative to a positive value or from a positive to a negati~e value as determined by the TRIG -/+ selection signal. When the selected analog signal does not normally change polarity, it can be offset half way from zero by conventional off-set circuit means at the input to A/D converter 32 so that there wiil be a shift of polarity at the start of the waveform for triggering purposes.
Although the illustrative embodiment of the in-vention has been described in considerable detail for the purpose of fully disclosing a practical operative struc-lC ture incorporating the invention, it is to be understood that the particular apparatus shown and described is in-tended to be illustrative only and that the various novel features of the invention may be incorporated in other structural forms without departing from the spirit and scope of the invention as defined in the subjoined claims.
Claims (17)
1. Apparatus for displaying an analog signal which occurs in a computer controlled machine tool circuit on an analog display device which is located in a site remote from the machine tool site, comprising:
probe means for picking up the desired analog signal in said machine tool circuit;
an analog to digital converter coupled to the output of said probe means for converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corres-ponding time;
means for applying the digital output of said analog to digital converter to a first memory which is associated with said machine control computer for storage;
means for transmitting said sequence of digital signals stored in said first memory to said remote site;
means at said remote site for receiving said trans-mitted sequence of digital signals;
a second memory at said remote site;
means for applying said received sequence of digital signals to said second memory for storage;
a digital to analog converter at said remote site;
means for applying said sequence of digital signals stored in said second memory to said digital to analog con-verter for conversion into an approximation of said analog signal; and analog display means coupled to the output of said digital to analog converter for displaying said approximation of said analog signal.
probe means for picking up the desired analog signal in said machine tool circuit;
an analog to digital converter coupled to the output of said probe means for converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corres-ponding time;
means for applying the digital output of said analog to digital converter to a first memory which is associated with said machine control computer for storage;
means for transmitting said sequence of digital signals stored in said first memory to said remote site;
means at said remote site for receiving said trans-mitted sequence of digital signals;
a second memory at said remote site;
means for applying said received sequence of digital signals to said second memory for storage;
a digital to analog converter at said remote site;
means for applying said sequence of digital signals stored in said second memory to said digital to analog con-verter for conversion into an approximation of said analog signal; and analog display means coupled to the output of said digital to analog converter for displaying said approximation of said analog signal.
2. The apparatus of claim 1 and also comprising a clock pulse circuit coupled to said analog to digital converter to control the operation thereof, said analog to digital converter being operable to perform an analog to digital conversion at the start of each clock period;
means for entering each digital output number pro-duced by said analog to digital conversion into said first memory before the next analog to digital conversion;
means for counting the number of digital output numbers entered into said first memory and means for terminating the entry of said digital out-put numbers into said first memory after a predetermined total number have been entered therein.
means for entering each digital output number pro-duced by said analog to digital conversion into said first memory before the next analog to digital conversion;
means for counting the number of digital output numbers entered into said first memory and means for terminating the entry of said digital out-put numbers into said first memory after a predetermined total number have been entered therein.
3. The apparatus of claim 2 wherein said means for counting the number of digital output numbers entered into said first memory and terminating the entry of said digital output numbers after a predetermined total has been reached comprises:
a counter;
means for presetting said counter to the desired total number of digital output numbers to be entered in said first memory;
means for decrementing said counter each time a digital output word is entered in said first memory; and means for generating a termination signal when said counter returns to zero.
a counter;
means for presetting said counter to the desired total number of digital output numbers to be entered in said first memory;
means for decrementing said counter each time a digital output word is entered in said first memory; and means for generating a termination signal when said counter returns to zero.
4. The apparatus of claim 2 and also comprising an address counter for said first memory;
means coupling the output of said address counter to said first memory to determine the addresses of said digital output numbers entered therein;
means for entering an initial address number in said address counter specifying the address of the first digital output number to be entered in said first memory; and means for incrementing said address counter every time a digital output number is entered into said first memory.
means coupling the output of said address counter to said first memory to determine the addresses of said digital output numbers entered therein;
means for entering an initial address number in said address counter specifying the address of the first digital output number to be entered in said first memory; and means for incrementing said address counter every time a digital output number is entered into said first memory.
5. The apparatus of claim 1 wherein said first memory is a memory portion of said machine tool computer.
6. The apparatus of claim 5 and also comprising a diagnostic computer at said remote site, and wherein said second memory comprises a memory portion of said diagnostic computer.
7. The apparatus of claim 6 wherein said means for transmitting said sequence of digital numbers from said first memory to said second memory comprises a first modem at said machine tool site coupled to said machine tool computer and said first memory portion thereof;
a second modem at said remote site coupled to said diagnostic computer and said second memory portion thereof;
and a digital transmission link extending between said first and second modems to transmit said sequence of digital signals from said first memory to said second memory.
a second modem at said remote site coupled to said diagnostic computer and said second memory portion thereof;
and a digital transmission link extending between said first and second modems to transmit said sequence of digital signals from said first memory to said second memory.
8. The apparatus of claim 7 wherein said digital transmission link includes a telephone line extending between said first and second modems.
9. Apparatus for displaying an analog signal which occurs in a computer controlled machine tool circuit on an analog display device which is located in a site remote from the machine tool site comprising:
probe means for picking up the desired analog signal in said machine tool circuit;
an analog to digital converter coupled to the output of said probe means for converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corres-ponding time;
means for transmitting said sequence of digital signals to said remote site;
means at said remote site for receiving said trans-mitted sequence of digital signals;
a digital to analog converter at said remote site for converting said sequence of digital signals into an approxi-mation of said analog signal; and analog display means coupled to the output of said digital to analog converter for displaying said approximation of said analog signal.
probe means for picking up the desired analog signal in said machine tool circuit;
an analog to digital converter coupled to the output of said probe means for converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corres-ponding time;
means for transmitting said sequence of digital signals to said remote site;
means at said remote site for receiving said trans-mitted sequence of digital signals;
a digital to analog converter at said remote site for converting said sequence of digital signals into an approxi-mation of said analog signal; and analog display means coupled to the output of said digital to analog converter for displaying said approximation of said analog signal.
10. The apparatus of claim 9 and also comprising a clock pulse circuit coupled to said analog to digital converter to control the operation thereof, said clock pulse circuit in-cluding an oscillator and a clock counter coupled to the out-put of said oscillator, the overflow signal of said counter comprising the output of said clock pulse circuit.
11. The apparatus of claim 10 and also comprising means for preloading a predetermined binary number into said clock counter every time it overflows to determine the length of its counting cycle to provide a clock period which is propor-tional to said predetermined binary number.
12. The apparatus of claim 9 wherein said analog display means has a vertical deflection input and a horizontal deflec-tion input, the output of said digital to analog converter being coupled to said vertical deflection input.
13. The apparatus of claim 12 and further comprising a second digital to analog converter;
means for coupling a sequence of digital numbers which represent a horizontal sweep voltage to the input of said second digital to analog converter; and the output of said second digital to analog con-verter being coupled to said horizontal deflection input.
means for coupling a sequence of digital numbers which represent a horizontal sweep voltage to the input of said second digital to analog converter; and the output of said second digital to analog con-verter being coupled to said horizontal deflection input.
14. The apparatus of claim 13 wherein the digital inputs of both digital to analog converters are coupled in parallel to a common data bus.
15. The apparatus of claim 14 and also including a plurality of data latches coupled in series between the digital inputs to each digital to analog converter and said common data bus; and means for selectively clocking said data latches to enter the digital data on said common data bus into a selected one of said digital to analog converters while the data latches for the other digital to analog converter retain the data previously entered therein.
16. A method of displaying an analog signal which occurs in a computer controlled machine tool circuit on an analog display device which is located in a site remote from the machine site, comprising the steps of:
(A) selecting a clock period to be used in converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corresponding time;
(B) selecting the total number of digital signals to be included in said sequence of digital signals;
(C) converting the instantaneous amplitude of said analog signal to a corresponding digital number at the beginn-ing of each successive clock period;
(D) counting the number of digital numbers generated in step (C);
(E) terminating the analog to digital conversion when the number of digital numbers generated in step (C) equals the total number selected in step (B);
(F) transmitting said sequence of digital signals to said remote site;
(G) converting said sequence of digital signals into an approximation of said analog signal at said remote site; and (H) applying said analog signal approximation to said analog display device to display said analog signal approxima-tion thereon.
(A) selecting a clock period to be used in converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corresponding time;
(B) selecting the total number of digital signals to be included in said sequence of digital signals;
(C) converting the instantaneous amplitude of said analog signal to a corresponding digital number at the beginn-ing of each successive clock period;
(D) counting the number of digital numbers generated in step (C);
(E) terminating the analog to digital conversion when the number of digital numbers generated in step (C) equals the total number selected in step (B);
(F) transmitting said sequence of digital signals to said remote site;
(G) converting said sequence of digital signals into an approximation of said analog signal at said remote site; and (H) applying said analog signal approximation to said analog display device to display said analog signal approxima-tion thereon.
17. A method of displaying an analog signal which occurs in a computer controlled machine tool circuit on an analog display device which is located in a site remote from the machine tool site, comprising the steps of:
(A) selecting a clock period to be used in converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corresponding time;
(B) selecting the total number of digital signals to be included in said sequence of digital signals;
(C) converting the instantaneous amplitude of said analog signal to a corresponding digital number at the beginn-ing of each successive clock period;
(D) counting the number of digital numbers generated in step (C);
(E) terminating the analog to digital conversion when the number of digital numbers generated in step (C) equals the total number selected in step (B);
(F) storing said sequence of digital signals in a first memory which is associated with said machine tool computer;
(G) reading said sequence of digital signals out of said first memory;
(H) transmitting said sequence of digital signals read out of said first memory to said remote site in which said analog display device is located;
(I) receiving said transmitted sequence of digital signals at said remote site;
(J) storing said received sequence of digital signals in a second memory located in said remote site;
(K) reading said sequence of digital signals out of said second memory;
(L) converting said sequence of digital signals read out of said second memory into an approximation of said analog signal; and (M) applying said analog signal approximation to said analog display device to display said analog signal approxima-tion.
(A) selecting a clock period to be used in converting said analog signal into a sequence of digital signals each of which represents the instantaneous amplitude of said analog signal at a corresponding time;
(B) selecting the total number of digital signals to be included in said sequence of digital signals;
(C) converting the instantaneous amplitude of said analog signal to a corresponding digital number at the beginn-ing of each successive clock period;
(D) counting the number of digital numbers generated in step (C);
(E) terminating the analog to digital conversion when the number of digital numbers generated in step (C) equals the total number selected in step (B);
(F) storing said sequence of digital signals in a first memory which is associated with said machine tool computer;
(G) reading said sequence of digital signals out of said first memory;
(H) transmitting said sequence of digital signals read out of said first memory to said remote site in which said analog display device is located;
(I) receiving said transmitted sequence of digital signals at said remote site;
(J) storing said received sequence of digital signals in a second memory located in said remote site;
(K) reading said sequence of digital signals out of said second memory;
(L) converting said sequence of digital signals read out of said second memory into an approximation of said analog signal; and (M) applying said analog signal approximation to said analog display device to display said analog signal approxima-tion.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/767,142 US4109309A (en) | 1977-02-09 | 1977-02-09 | Method and apparatus for remote display of analog signals occurring in computer controlled machine tools |
| US767,142 | 1977-02-09 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1106974A true CA1106974A (en) | 1981-08-11 |
Family
ID=25078607
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA295,646A Expired CA1106974A (en) | 1977-02-09 | 1978-01-25 | Method and apparatus for remote display of analog signals occurring in computer controlled machine tools |
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| JP (1) | JPS5399963A (en) |
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| JP4119295B2 (en) * | 2003-04-07 | 2008-07-16 | 東京エレクトロン株式会社 | Maintenance / diagnosis data storage server, maintenance / diagnosis data storage / acquisition system, maintenance / diagnosis data storage / provision system |
| US7894934B2 (en) * | 2006-12-05 | 2011-02-22 | Veyance Technologies, Inc. | Remote conveyor belt monitoring system and method |
| US7690354B2 (en) * | 2006-12-05 | 2010-04-06 | Ford Global Technologies, Llc | System and method for improving operation of a fuel injector at lower temperatures |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3376465A (en) * | 1964-10-16 | 1968-04-02 | Stromberg Carlson Corp | Color character display |
| US3689879A (en) * | 1971-05-18 | 1972-09-05 | Baxter Laboratories Inc | Conservation of transient pulses in analog to digital conversion |
| US3910257A (en) * | 1973-04-25 | 1975-10-07 | Nasa | Medical subject monitoring systems |
| US3882305A (en) * | 1974-01-15 | 1975-05-06 | Kearney & Trecker Corp | Diagnostic communication system for computer controlled machine tools |
| US3990036A (en) * | 1974-02-28 | 1976-11-02 | Western Geophysical Co. | Multiplexing method and apparatus for telemetry of seismic data |
| US4048635A (en) * | 1975-09-15 | 1977-09-13 | Texaco Inc. | Seismic playback/monitor system |
-
1977
- 1977-02-09 US US05/767,142 patent/US4109309A/en not_active Expired - Lifetime
-
1978
- 1978-01-04 IL IL53751A patent/IL53751A/en unknown
- 1978-01-18 ZA ZA00780331A patent/ZA78331B/en unknown
- 1978-01-19 IN IN51/DEL/78A patent/IN148413B/en unknown
- 1978-01-19 NZ NZ186264A patent/NZ186264A/en unknown
- 1978-01-24 AU AU32668/78A patent/AU508540B2/en not_active Expired
- 1978-01-25 CA CA295,646A patent/CA1106974A/en not_active Expired
- 1978-01-26 GR GR55279A patent/GR74532B/el unknown
- 1978-01-26 DE DE19782803394 patent/DE2803394A1/en not_active Ceased
- 1978-01-31 AT AT0066078A patent/AT364985B/en not_active IP Right Cessation
- 1978-02-01 TR TR20554A patent/TR20554A/en unknown
- 1978-02-01 NO NO780352A patent/NO780352L/en unknown
- 1978-02-03 FI FI780352A patent/FI780352A/en not_active Application Discontinuation
- 1978-02-03 BR BR7800745A patent/BR7800745A/en unknown
- 1978-02-04 ES ES466662A patent/ES466662A1/en not_active Expired
- 1978-02-06 PT PT67620A patent/PT67620B/en unknown
- 1978-02-06 GB GB4642/78A patent/GB1596576A/en not_active Expired
- 1978-02-06 CH CH130178A patent/CH629135A5/en not_active IP Right Cessation
- 1978-02-06 IE IE257/78A patent/IE46057B1/en unknown
- 1978-02-07 FR FR7803354A patent/FR2380595A1/en active Granted
- 1978-02-07 IT IT47954/78A patent/IT1101752B/en active
- 1978-02-07 SE SE7801422A patent/SE445589B/en unknown
- 1978-02-07 BE BE184958A patent/BE863719A/en not_active IP Right Cessation
- 1978-02-08 DK DK57178A patent/DK57178A/en not_active Application Discontinuation
- 1978-02-08 LU LU79029A patent/LU79029A1/en unknown
- 1978-02-08 JP JP1253278A patent/JPS5399963A/en active Pending
- 1978-02-08 YU YU00291/78A patent/YU29178A/en unknown
- 1978-02-08 NL NLAANVRAGE7801473,A patent/NL172700C/en active Search and Examination
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