JP4197639B2 - Encoder inspection device - Google Patents

Description

  The present invention relates to an encoder inspection apparatus that inspects an output signal of an encoder.

  Generally, a processing machine is provided with an actuator such as a servomotor for operating a workpiece or a table and an encoder for detecting the operation of the actuator. In particular, the encoder is an important part that directly affects the machining accuracy of the workpiece. If the encoder has a poor performance or malfunctions, or the mounting accuracy is poor, the machining accuracy of the workpiece. Decreases. Therefore, it is desired to precisely inspect the output signal of the encoder in a state where it is incorporated in a processing machine.

  As the encoder inspection apparatus, a reference encoder having a resolution n times that of the inspection target encoder is provided coaxially with respect to the inspection target encoder, and a difference signal between a signal obtained by multiplying the output of the inspection target encoder by n and the reference encoder signal Has been proposed (see, for example, Patent Document 1).

Japanese Patent Publication No. 4-2885

  However, according to the prior art according to Patent Document 1 described above, the inspection cannot be performed unless the drive motor and the reference encoder are attached to the inspection target encoder, and the encoder already incorporated in the processing machine is removed from the processing machine. It is difficult to perform the inspection without removing it.

  Moreover, the output signal of the encoder to be inspected has an A phase signal and a B phase signal having different phases, but according to the prior art according to Patent Document 1, an inspection is performed to individually inspect the A phase signal and the B phase signal. It takes a long time, and it is difficult to inspect the relative relationship between the phase A signal and the phase B signal such as a phase difference.

  Furthermore, according to the conventional inspection apparatus, it is possible to inspect for a serious defect such as the presence or absence (or phase loss) of the pulse of the A phase signal or the B phase signal, but the duty ratio and the phase difference of the pulse are precisely Could not be inspected. That is, if the pulse duty ratio or phase difference is not correct in the output signal of the encoder, measure the machining accuracy of the workpiece after machining the workpiece with a machining machine using the encoder. Thus, there is no choice but to perform secondary inspection means for judging the quality of the encoder.

  The present invention has been made in consideration of such problems, and the time required for the inspection is short, and the output signal of the encoder incorporated in the existing equipment such as a processing machine is inspected accurately without removing it from the equipment. An object of the present invention is to provide an encoder inspection apparatus that makes it possible.

An encoder inspection apparatus according to the present invention is an encoder inspection apparatus that inspects an encoder that outputs an A-phase signal and a B-phase signal that are different in phase with rotation when rotated by a rotation means, and the rotation means Clock generating means for generating a clock faster than the frequency of the pulses of the A-phase signal and the B-phase signal when the encoder is rotated at a predetermined speed, and rising edges and rising edges of the A-phase signal and the B-phase signal A signal dividing circuit that divides one cycle of the pulse into four sections at the timing of the falling edge, a counting circuit that counts the clock for each of the four sections, and for each of the four sections counted by the counting circuit Inspection means for inspecting the encoder based on the count value, measurement data based on the count value for each period, and previous A display unit that selectively displays one or both of characteristic data indicating typical characteristics of measurement data, a condition input unit that inputs the resolution of the encoder and the rotation speed of the rotating unit, and the four sections have a, a clock setting unit for setting an operating condition of said clock generating means so that the number of the clock becomes a value within a predetermined range, wherein the display unit, a total of the each of the four sections as the measurement data The maximum value and the minimum value among the numerical values measured a plurality of times are displayed including a data distribution window that displays bars in every four sections .

  Thus, by dividing one cycle into four sections and counting the clock for each section, the A-phase signal and the B-phase signal can be inspected at the same time. Therefore, the inspection time can be shortened. In addition, since it is possible to perform inspections with installation errors included without removing encoders installed in existing facilities, inspections can be performed in actual operating conditions, and the reliability of the inspection Will be improved. Further, the phase difference between the A-phase signal and the B-phase signal and the duty ratios of the A-phase signal and the B-phase signal can be confirmed based on the counted number of clocks.

  Accordingly, a detailed inspection or a simple inspection can be selected according to the inspection application, and the inspection time including data communication, processing, and display can be shortened in the simple inspection.

As described above, the clock frequency can be set based on the resolution and the rotation speed of the encoder, and the inspection accuracy can be improved by setting the number of clocks for each predetermined section to a value within a predetermined range. it can.
The encoder may be provided in a predetermined processing machine. The clock setting unit may automatically set the number of the clocks in each of the four sections so as to be a value in a range of 20 to 80% of an allowable maximum count value of the coefficient circuit.

Furthermore, the inspection means by the this inspecting based on the phase ratio is the ratio of the sum of the the regimen values for count values for each of the four sections, overall both A-phase and B-phase signals And it can be inspected precisely.

  According to the encoder inspection apparatus according to the present invention, one cycle of the A-phase signal and the B-phase signal is divided into four sections, and the inspection is performed based on the count value obtained by counting the clock for each section. The signal and the B phase signal can be inspected at the same time, and the inspection time can be shortened. Since the A phase signal and the B phase signal of the encoder can be inspected at the same time, an efficient and precise inspection can be performed.

  Moreover, since the encoder can be inspected under actual use conditions while being incorporated in existing equipment, the reliability of the inspection result is high.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an encoder inspection apparatus according to the present invention will be described with reference to FIGS.

  As shown in FIG. 1, an encoder inspection apparatus 10 according to the present embodiment is connected to a processing machine 12 and outputs from a first encoder 14a, a second encoder 14b, and a third encoder 14c provided in the processing machine 12. The signal is inspected. The first to third encoders 14a, 14b, and 14c output three signals of an A phase signal, a B phase signal, and a Z phase signal, respectively.

  The processing machine 12 performs predetermined processing on the workpiece 16 and includes a processing machine main body 18 and a control panel 20. The processing machine main body 18 includes a first motor (rotating unit) 24 that rotates a tool 22 that processes the workpiece 16 and a second motor (rotating unit) that rotates the workpiece 16 in synchronization with the rotation of the tool 22. 26, a table 28 on which the workpiece 16 and the second motor 26 are provided, and a third motor (rotating means) 30 for sliding the table 28. The first motor 24, the second motor 26, and the third motor 30 are each driven by the control panel 20, and the output signals of the first encoder 14a, the second encoder 14b, and the third encoder 14c are transmitted to the control panel 20. The rotation angle and rotation speed can be detected.

  The encoder inspection apparatus 10 takes in and processes the measurement unit 36 that processes the output signals of the first encoder 14a, the second encoder 14b, and the third encoder 14c, and the signal measured by the measurement unit 36 via the communication unit 37. And a personal computer 32 for display. The communication means 37 is provided as a standard in a general personal computer 32, and the communication speed is slightly low.

  The personal computer 32 includes a main body (inspection means) 38, a monitor 40 as output means, a keyboard 42 and a mouse 44 as input means.

  As shown in FIG. 2, the measurement unit 36 includes a signal switch 34 that selectively switches and takes in one of the output signals of the first to third encoders 14 a, 14 b, and 14 c, an A phase signal, and a B phase signal Is a clock oscillator (clock generation means) that can change the frequency of the clock ck that is output based on instructions from the four AND gates (signal division circuits) 50a, 50b, 50c, 50d and the CPU (inspection means) 52 54, and four AND gates 56a, 56b, 56c, 56d in which the clock ck is input to one input terminal and the output signals a1, a2, a3, a4 of the AND gates 50a to 50d are input to the other input terminal, respectively. Have

  In FIGS. 1 and 2, the output signals of the first to third encoders 14a, 14b, and 14c are each represented by one signal line. However, in actuality, as described above, the A-phase signal, the B-phase signal, and It consists of three output signals of the Z phase signal. The A-phase signal and the B-phase signal are pulse signals corresponding to the resolution (or pulsed waveform signals) and have a phase difference of 90 ° from each other in the normal state. The Z-phase signal is a pulse signal indicating a rotation reference point, and is output once per rotation.

  The measurement unit 36 includes four counters (counting circuits) 58a, 58b, 58c, 58d that count the number of pulses of the output signals b1, b2, b3, b4 of the AND gates 56a, 56b, 56c, 56d, A DMA (Direct Memory Access) controller 60 that records the count values d1 to d4 by the counters 58a to 58d, and four AND gates 62a, 62b, 62c, and 62d that instruct the DMA controller 60 to read data. Have. For the counters 58a to 58d, for example, a counter capable of counting up to about 255 (8 bits) may be used.

  Furthermore, the measurement unit 36 includes a start / stop control unit 64 that determines the start / end of measurement based on an instruction from the CPU 52 and a Z-phase signal.

The AND gates 50a, 50b, 50c, and 50d are configured to obtain the logical product of the A-phase signal, the B-phase signal, and the inverse logic signal, respectively. The output signals a1 to a4 are represented by the following logical expressions. Is done.
a1 = A ・ B
a2 = NOT (A) ・ B
a3 = NOT (A) / NOT (B)
a4 = A · NOT (B)

  However, “A” indicates an A phase signal, “B” indicates a B phase signal, “NOT” indicates an inverse logic, and “·” indicates a logical product.

  An output signal b1 that is a logical product of the output signal a1 of the AND gate 50a and the clock ck is input to the counter 58a and counted. Further, when the output signal a4 of the AND gate 50d is input to the reset terminal of the counter 58a, the count value d1 is reset to “0” when the output signal a4 is switched, and the output signal a4 is at the LOW level. The pulses of the output signal a1 are counted.

  Similarly, the output signal a1 is input to the reset terminal of the counter 58b, and the pulses of the output signal a2 are counted when the output signal a1 is at the LOW level. An output signal a2 is input to the reset terminal of the counter 58c, and the pulse of the output signal a3 is counted when the output signal a2 is at the LOW level. An output signal a3 is input to the reset terminal of the counter 58d, and the pulse of the output signal a4 is counted when the output signal a3 is at the LOW level.

  The AND gate 62a receives the output signal en of the start / stop control unit 64 and the output signal a4 of the AND gate 50d, and has a function of giving a transfer instruction to the DMA controller for the count value d1 of the counter 58a. When the output signal c1 of the AND gate 62a rises, that is, when the output signal en4 is HIGH and the output signal a4 rises, the DMA controller 60 can read the count value d1 of the counter 58a.

  Similarly, the output signals en are input to the AND gates 62b, 62c, and 62d, and the output signals a1, a2, and a3 are input thereto, respectively. Therefore, the AND gates 62b, 62c, and 62d can cause the DMA controller 60 to read the count values d2, d3, and d4 of the counters 58b, 58c, and 58d when the output signals a1, a2, and a3 rise.

  The DMA controller 60 transfers the count values d1 to d4 from the data signal line dt to the RAM 70 at a predetermined timing. At this time, the DMA controller 60 can transfer the count values d1 to d4 while designating an address to be stored for each signal by the address signal line adr. This transfer process is executed a plurality of times while the output signal en is HIGH, and the count values d1 to d4 counted by the counters 58a to 58d are sequentially transferred from the DMA controller 60 to the RAM 70 while changing addresses.

  As shown in FIG. 3, the output signal en is selected by the signal switcher 34 (hereinafter referred to as an inspection target encoder) during the rise of the two Z-phase signals, that is, among the first to third encoders 14a, 14b, and 14c. Is also HIGH (in FIG. 3, each signal is HIGH at the upper side and LOW at the lower side). Further, as described above, the A-phase signal and the B-phase signal are input as pulse signals having a phase difference of 90 °.

  The output signals a1 to a4 are divided by the timing of the rising edge and the falling edge of the A phase signal and the B phase signal, and one period T of the A phase signal (or B phase signal) is divided into four sections T1, T2, T3. And T4. As is apparent from FIG. 2, this dividing operation is realized by a simple circuit including AND gates 50a to 50d.

  Further, the output signal b1 is counted by the counter 58a as the number of pulses of the clock ck in the section T1, and read into the DMA controller 60 as the count value d1. Similarly, the output signals b2, b3, and b4 are counted as the number of pulses of the clock ck in the sections T2, T3, and T4, and are read into the DMA controller 60 as the counted values d2, d3, and d4.

  In FIG. 3, the frequency of the clock ck is set so that d1 to d4 each have a value of about “5” so that the drawing is not complicated, but in practice, d1 to d4 are counters 58a to 58d. The clock ck may be set so as to be as large as possible within a countable range. By setting in this way, the inspection target encoder can be inspected more precisely.

  As shown in FIG. 4, the CPU 52 calculates the phase ratio (measurement data) p1, p2, p3, and p4 of the A phase signal and the B phase signal based on the count values d1 to d4 read from the RAM 70. 72, a duty ratio calculation unit 74 that calculates the duty ratios (measurement data) r1 and r2, and a characteristic data calculation unit 76 that calculates the characteristic data of the count values d1 to d4, the phase ratios p1 to p4, or the duty ratios r1 and r2. An abnormality determination unit (inspection means) 78 that determines the quality of these data and outputs a determination result to a predetermined external device, and an abnormality detection level setting unit 80 that sets a determination reference value in the abnormality determination unit 78 Have

  Further, the CPU 52 sets the operating conditions of the signal switch 34 and the clock oscillator 54 based on the communication control unit 82 capable of mutual communication with the personal computer 32 and the data received via the communication control unit 82. And a condition setting unit 84. Of these, the operating condition of the clock oscillator 54 is set by the clock setting unit 85.

  The phase ratio calculation unit 72, the duty ratio calculation unit 74, the characteristic data calculation unit 76, and the abnormality determination unit 78 may be provided in the personal computer 32.

Here, the phase ratios p1, p2, p3, and p4 are numerical values expressed in angular units by multiplying the ratio of the sum of the count values d1 to d4 (d1 + d2 + d3 + d4) to the respective count values d1 to d4 by 360 °. 90 ° is desirable. The phase ratios p1 to p4 are expressed by the following equations.
p1 = d1 / (d1 + d2 + d3 + d4) × 360≈T1 / T × 360
p2 = d2 / (d1 + d2 + d3 + d4) × 360≈T2 / T × 360
p3 = d3 / (d1 + d2 + d3 + d4) × 360≈T3 / T × 360
p4 = d4 / (d1 + d2 + d3 + d4) × 360≈T4 / T × 360

The duty ratios r1 and r2 are numerical values expressed as a percentage by multiplying the ratio of the HIGH section with respect to one cycle in the A-phase signal and the B-phase signal by 100 [%], and are 50 [%]. Is desirable. The duty ratios r1 and r2 are expressed by the following equations.
r1 = (d1 + d4) / (d1 + d2 + d3 + d4) × 100
r2 = (d 3 + d2) / (d1 + d2 + d3 + d4) × 100

  According to the phase ratios p1 to p4 and the duty ratios r1 and r2, it is possible to comprehensively inspect both the A phase signal and the B phase signal. In particular, not only a serious abnormality such as a missing phase of the pulse but also a duty of the pulse The ratio and the phase difference between the A-phase signal and the B-phase signal can also be inspected precisely.

  Further, since the phase ratios p1 to P4 are detected for each cycle (one period T), it is difficult to be affected by the rotation unevenness of the encoder, and a more precise inspection is possible.

  Furthermore, the characteristic data is a representative numerical value indicating the characteristics of a plurality of data groups, such as an average value, a maximum value, a minimum value, and an analysis value (for example, 3σ value) by a statistical method.

  The phase ratio calculation unit 72, the duty ratio calculation unit 74, the characteristic data calculation unit 76, the abnormality determination unit 78, the abnormality detection level setting unit 80, the communication control unit 82, and the condition setting unit 84 are actually predetermined. It acts under the control of the CPU 52 as software processing by a program. The program is read by the CPU 52 from a recording medium (not shown), a ROM (Read Only Memory), a communication line, etc., and is processed and executed in cooperation with hardware such as the RAM 70.

  Next, a screen (display unit) 100 relating to inspection result information displayed on the monitor 40 of the personal computer 32 will be described with reference to FIG. The screen 100 is operated by a predetermined operation (for example, click or drag) using a pointing device such as the mouse 44 or a key input using the keyboard 42.

  As shown in FIG. 5, the screen 100 includes a start angle setting slide bar 102 and an end angle setting slide bar 104 for setting a read start angle and a read end angle of a signal read from the measurement unit 36, and first to third encoders 14a. Encoder switching button 106 for selecting one of the encoders to be inspected from .about.14c. The readout start angle set by the start angle setting slide bar 102 is numerically displayed on the display unit 102a, and the readout end angle set by the end angle setting slide bar 104 is numerically displayed on the display unit 104a. In the initial state, the read start angle is 0 ° and the read end angle is 360 °.

  The screen 100 also includes a resolution measurement button 108 that measures the resolution of the encoder to be inspected once, a resolution continuous measurement button 110 that continuously measures, a phase inspection execution button 111 that measures the phase ratio, and a phase ratio display. The actual phase value switching button 112 for switching the display in the unit 126 from the display of the phase ratios p1 to p4 to the display of the count values d1 to d4 and the oscillation frequency of the clock oscillator 54 (see FIG. 2) are set automatically and manually. A clock setting unit 114 and a clock value display unit 116; The resolution value of the inspection target encoder measured by the inspection is displayed on the pulse measurement result display unit 134.

  The screen 100 also has a resolution setting unit (condition input unit) 118 for inputting the resolution of the inspection target encoder selected by the encoder switching button 106.

  The setting contents in the clock setting unit 114 are transmitted to the clock setting unit (see FIG. 4) 85 of the condition setting unit 84. When a predetermined value is input (or selected) to the clock setting unit 114, the clock setting unit 85 sets the oscillation frequency of the clock oscillator 54 based on the value. When the clock setting unit 114 instructs automatic setting (for example, “AUTO” is displayed), the frequency of the clock ck by the clock oscillator 54 is set within a predetermined range with reference to the actual speed measurement value of the encoder pulse. Automatically set to be a value. That is, the count values d1 to d4 that are the number of clocks ck in each of the four sections T1, T2, T3, and T4 are set to be a necessary and sufficient number. For example, the count values d1 to d4 are set to the counters 58a to 58d. Is automatically set to a value in the range of 20 to 80% with respect to the allowable maximum count value.

  Further, the screen 100 displays a phase ratio display unit 126 that displays the phase ratios p1 to p4 and the duty ratios r1 and r2 in a graph format corresponding to the set values of the start angle setting slide bar 102 and the end angle setting slide bar 104, respectively. Duty ratio display unit 128, distribution result drawing window 130 that displays the distribution of phase ratios p1 to p4 and duty ratios r1 and r2, and A phase signal and B phase signal are reproduced and displayed based on count values d1 to d4. An encoder waveform monitor unit 132 for performing the processing, and a data distribution window 150 showing the distribution of the count values d1 to d4. The waveform of symbol A in the encoder waveform monitor unit 132 indicates the A phase signal, and the waveform of symbol B indicates the B phase signal.

  The phase ratio display unit 126, the duty ratio display unit 128, the distribution result drawing window 130, and the data distribution window 150 are set to a predetermined operation (for example, click) after the cursor linked to the mouse 44 is set to each drawing area. As a result, the corresponding data is read from the measurement unit 36 via the communication means 37 and displayed on each display unit. That is, display / non-display can be switched for each display unit.

  The phase ratio display unit 126 and the duty ratio display unit 128 display the phase ratios p1 to p4 and the duty ratios r1 and r2 obtained by the measurement unit 36 for each color.

  The distribution result drawing window 130 is an area for displaying the distribution of the phase ratios p1 to p4 and the duty ratios r1 and r2, and the vertical axis is represented by the number of distributions [%]. The horizontal axis is 0 to 180 ° with respect to the phase ratios p1 to p4, and 0 to 100% with respect to the duty ratios r1 and r2.

  In addition, six curves are drawn in the distribution result drawing window 130, and displaying all of them may be somewhat complicated. In such a case, display / non-display can be switched for each curve by operating the display designation check boxes 140a, 140b, 140c, 140d, 140e, and 140f corresponding to the six curves.

The data distribution window 150 reads the maximum value and the minimum value of the count values d1, d2, d3, and d4 from the characteristic data calculation unit 76 of the measurement unit 36, and displays them in the bar format on the display bars 150a, 150b, 150c, and 150d, respectively. It is displayed as a percentage value with respect to the maximum allowable count value of the counters 58a to 58d.

  According to the data distribution window 150, it is possible to easily confirm whether or not the inspection itself is normally performed and whether the count values d1 to d4 of the inspection result are normal or abnormal. That is, it can be determined that the count values d1 to d4 are normal when the values of the bars substantially match and the width is narrow. When the width of each bar is wide, it can be determined that the variation of the count values d1 to d4 is large. When each bar reaches 100 [%], it can be determined that the allowable maximum count value of the counters 58a to 58d has overflowed, and the clock setting unit 114 may be reset to a smaller value. Further, when each bar has a value close to 0 [%], it can be determined that the values of the count values d1 to d4 are too small and the inspection accuracy is insufficient. In this case, the value of the clock setting unit 114 may be reset larger. When the clock oscillator 54 is automatically set by the clock setting unit 114, the clock frequency is automatically set to an appropriate value.

  In order to display the data distribution window 150, only the maximum value and the minimum value of the count values d1 to d4 have to be read from the measurement unit 36, so that the transfer time by the communication means 37 is very short. Therefore, when simple inspection is sufficient (for example, during daily pre-start inspection), the quality of the output signal of the inspection target encoder may be determined by displaying the data distribution window 150.

  Furthermore, the phase ratio display unit 126 and the duty ratio display unit 128 may be displayed only when more detailed data needs to be confirmed in a periodic detailed function inspection or the like. The display / non-display of the phase ratio display unit 126, the duty ratio display unit 128, and the data distribution window 150 may be switched by operating each display unit with the mouse 44 as described above.

  Next, a procedure for inspecting the output signals of the first to third encoders 14a, 14b, and 14c using the encoder inspection apparatus 10 configured as described above will be described.

  First, the measurement unit 36 is turned on and a predetermined program is started up in the personal computer 32 to display the screen 100 on the screen of the monitor 40.

  Next, on the screen 100, the encoder switching button 106 is operated to select the inspection target encoder, and the resolution of the inspection target encoder is input to the resolution setting unit 118, and the oscillation frequency of the clock oscillator 54 is input by the clock setting unit 114. Set. By performing the input setting in the personal computer 32 in this way, the CPU 52 sets the operating conditions of the clock oscillator 54 and the signal switch 34 through the condition setting unit 84.

  Next, the inspection machine encoder is rotated by operating the processing machine 12 to rotate the first motor 24, the second motor 26, or the third motor 30.

  Further, the phase inspection execution button 111 on the screen 100 is operated to start measurement. In the measurement unit 36, each signal of the waveform shown in FIG. 3 is input and generated, and the count values d1 to d4 are transferred to the RAM 70 via the DMA controller 60.

  Next, after confirming that the measurement is completed, the operator operates the mouse 44 to display the maximum value and the minimum value of the count values d1 to d4 in the data distribution window 150 in a bar format. In order to display the data distribution window 150, the numerical values read from the measuring unit 36 are only the total eight values of the maximum values and the minimum values of the count values d1 to d4. Accordingly, reading is completed instantaneously, and the data distribution window 150 is displayed or updated instantaneously.

  Further, as described above, in the data distribution window 150, it is possible to make a rough determination as to whether the inspection target encoder output signal is good or bad.

  Further, in order to confirm the temporal change and detailed distribution of the phase ratios p1 to p4 and the duty ratios r1 and r2, the region of the phase ratio display unit 126, the duty ratio display unit 128 or the distribution result drawing window 130 is moved with the mouse 44. Manipulate. By this operation, all data (or data appropriately thinned out) of the count values d1 to d4, the phase ratios p1 to p4, and the duty ratios r1 and r2 are transmitted from the measurement unit 36 to the personal computer 32 via the communication unit 37. Displayed.

  At this time, it takes some time to read data from the measurement unit 36 to the personal computer 32. Although a higher-speed communication unit 37 can be used, the use of the general-purpose communication unit 37 even at a low speed reduces the number of models that can be used as the personal computer 32. On the other hand, when a simple inspection is sufficient, it is sufficient to observe the data distribution window 150 displayed instantaneously.

  When the bar displayed in the data distribution window 150 is close to 0 [%] or 100 [%], there is a possibility that the measurement accuracy is insufficient or the count values d1 to d4 overflow the allowable maximum count value. Therefore, it is preferable to operate the phase ratio display unit 126, the duty ratio display unit 128, or the distribution result drawing window 130 with the mouse 44 after re-inputting a value to the clock setting unit 114 and then performing remeasurement.

  The result of the inspection performed on the inspection target encoder is operated based on the waveforms displayed in the phase ratio display unit 126, the duty ratio display unit 128, the distribution result drawing window 130, the encoder waveform monitoring unit 132, and the data distribution window 150. The person may make a judgment of pass / fail.

  Regarding the phase ratio display unit 126 and the duty ratio display unit 128, as shown in FIG. 5, there is little variation in the vicinity of 90 ° or 50%, where the phase ratios p1 to p4 and the duty ratios r1 and r2 are the center lines, respectively. In this case, it can be judged as normal. On the other hand, as shown in FIG.

  When the phase ratios p1 to p4 are respectively displayed in the vicinity of 90 °, it is confirmed that the phase difference between the A-phase signal and the B-phase signal is 90 °, which is a normal value. Further, when the phase ratios p1 to p4 are deviated from 90 ° while the duty ratios r1 and r2 are close to 50%, it is confirmed that the phase difference between the A phase signal and the B phase signal is not 90 °.

  Further, regarding the distribution result drawing window 130 and the data distribution window 150, as shown in FIG. 6, when the curves and bars indicating the phase ratios p1 to p4 and the duty ratios r1 and r2 are narrow and narrow at the center. Can be judged normal. On the other hand, as shown in FIG. 6, when the width of each curve or bar is large and is greatly deviated from the center, it is determined as abnormal.

  Further, the quality may be determined by directly observing the waveforms of the A phase signal and the B phase signal displayed on the encoder waveform monitor unit 132.

  Furthermore, the determination of pass / fail may be automatically performed by the abnormality determination unit 78 without being visually checked by the operator. In this case, the determination may be made based on the phase ratios p1 to p4, the duty ratios r1 and r2, and the characteristic data thereof.

  The inspection target encoder determined to be abnormal may be replaced with a normal one and then checked again to confirm that it is normal before operating the processing machine 12. By doing in this way, the processing precision of the processing machine 12 can be kept highly accurate, and a processing defect and a reduction in processing precision can be prevented.

  As described above, according to the encoder inspection apparatus 10 according to the present embodiment, the A phase signal and the B phase signal of the inspection target encoder can be simultaneously inspected, so that an efficient and accurate inspection is performed. Can do. In particular, the phase difference between the A phase signal and the B phase signal and the duty ratio of the pulse are accurately obtained based on the count values d1 to d4. Thereby, the accuracy of the first to third encoders 14a, 14b, and 14c can be kept extremely high, and the processing accuracy of the workpiece 16 can be improved.

  Further, since the first to third encoders 14a, 14b, and 14c can be inspected under actual use conditions while being incorporated in the processing machine 12, the reliability of the inspection results is high.

  Furthermore, since the communication means 37 for the measurement unit 36 is a general-purpose device, a general personal computer 32 can be connected as a communication target device. Furthermore, when the communication speed of the communication unit 37 is low, the inspection time including the communication time can be shortened by performing simple display using the data distribution window 150 with a small amount of communication data.

  A predetermined binarization circuit may be inserted in the input part of the A phase signal and the B phase signal in the measurement unit 36 to deal with a case where the A phase signal and the B phase signal are sine waves.

  The phase ratio display unit 126, the duty ratio display unit 128, and the like are not limited to the graphic format and may be displayed in a numerical format. The phase ratio display unit 126 and the duty ratio display unit 128 may be provided with a zoom function for enlarging the vertical and horizontal axes.

  As the monitor 40, a keyboard 42 and a mouse 44 may be omitted by using a touch panel monitor. Furthermore, the encoder inspection apparatus 10 may be applied to a linear encoder.

  In the above embodiment, the encoder inspection device 10 is a separate device from the processing machine 12, and inspects the output signals of the first to third encoders 14a, 14b, 14c incorporated in the processing machine 12. However, the encoder inspection apparatus 10 is a dedicated inspection apparatus for the processing machine 12 and may be configured integrally with the control panel 20. In this case, if the resolution of the encoder to be inspected and the rotation speeds of the first motor 24, the second motor 26, and the third motor 30 are known, the input unit of the resolution setting unit 118 corresponding to these values is omitted. May be.

  Further, the encoder to be inspected is not limited to that incorporated in the existing equipment such as the processing machine 12, but for example, as shown in FIG. The encoder 160 may be inspected. The encoder inspection device 10 a has substantially the same configuration as the encoder inspection device 10, and includes a dedicated motor 164 for rotating the detachable encoder 160 via the coupling 162. A measurement board 166 corresponding to the measurement unit 36 is incorporated in the main body 38 of the personal computer 32. According to the encoder inspection device 10a, for example, when there are a large number of single encoders 160, it is possible to inspect them one by one in order. In the encoder inspection apparatus 10, since the measurement board 166 is incorporated in the main body 38, it is possible to directly access the internal bus, and a communication unit corresponding to the communication unit 37 is unnecessary. Further, the measurement board 166 may be applied to the encoder inspection apparatus 10 and the measurement unit 36 and the communication unit 37 may be omitted.

  The encoder inspection apparatus according to the present invention is not limited to the above-described embodiment, and it is needless to say that various configurations can be adopted without departing from the gist of the present invention.

1 is a perspective view of an encoder inspection apparatus and a processing machine according to the present embodiment. It is a block diagram of the configuration of the measurement unit. It is a time chart of the signal input and produced | generated in a measurement unit. It is a functional block diagram of a program processed by CPU. It is a screen displayed on a monitor when the inspection target encoder is normal. It is a screen displayed on a monitor when the inspection target encoder is abnormal. It is a perspective view of the encoder test | inspection apparatus which concerns on the modification of this Embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 10a ... Encoder inspection apparatus 12 ... Processing machine 14a, 14b, 14c, 160 ... Encoder 20 ... Control panel 24, 26, 30, 164 ... Motor 32 ... Personal computer 34 ... Signal switch 36 ... Measuring unit 37 ... Communication means 38 ... Main body 40 ... Monitors 50a-50d, 56a-56d, 62a-62d ... AND gate 52 ... CPU 54 ... Clock oscillator 58a-58d ... Counter 60 ... DMA controller 70 ... RAM 72 ... Phase ratio calculation unit 74 ... Duty ratio calculation Unit 76 ... characteristic data calculation unit 78 ... abnormality determination unit 80 ... abnormality detection level setting unit 84 ... condition setting unit 85 ... clock setting unit 100 ... screen 108 ... resolution measurement button 110 ... resolution continuous measurement button 111 ... phase inspection execution button 112 ... Real phase value switching button 114 ... Clock Tough 116 ... clock value display unit 118 ... resolution setting unit 126 ... phase ratio display section 128 ... duty ratio display section 130 ... distribution results rendering window 132 ... encoder waveform monitor unit 150 ... data distribution Wind

Claims (4)

An encoder inspection device that inspects an encoder that outputs an A-phase signal and a B-phase signal having different phases with rotation when rotated by a rotating means,
Clock generating means for generating a clock faster than the frequency of the pulses of the A-phase signal and the B-phase signal when the encoder is rotated at a predetermined speed by the rotating means;
A signal dividing circuit for dividing one period of the pulse into four sections at the timing of the rising edge and the falling edge of the A-phase signal and the B-phase signal;
A counting circuit that counts the clock every four intervals;
Inspection means for inspecting the encoder based on a count value for each of the four sections counted by the counting circuit;
A display unit that selectively displays one or both of measurement data based on the count value for each cycle and characteristic data indicating a representative characteristic of the measurement data;
A condition input unit for inputting the resolution of the encoder and the rotation speed of the rotating means;
A clock setting unit that sets operating conditions of the clock generation means so that the number of clocks in each of the four sections becomes a value within a predetermined range ;
I have a,
The display unit displays, as the measurement data, a data distribution window that displays a maximum value and a minimum value among the measured values of the four sections for a plurality of times, in a bar shape for each of the four sections. Encoder inspection device characterized. The encoder inspection apparatus according to claim 1,
An encoder inspection apparatus, wherein the encoder is provided in a predetermined processing machine. The encoder inspection apparatus according to claim 1,
The clock setting unit automatically sets the clock so that the number of clocks in each of the four sections becomes a value in a range of 20 to 80% of an allowable maximum count value of the coefficient circuit. apparatus. The encoder inspection apparatus according to claim 1,
The encoder inspection apparatus, wherein the inspection unit performs an inspection based on a phase ratio that is a ratio of a total of the count values to a count value for each of the four sections.

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