JPH05296794A - Measuring device - Google Patents

Abstract

PURPOSE:To improve reliability in judgement of unmeasurableness by latching a signal of a detecting system for fine detection in synchronizing with a signal of another detecting system for rough detection, and comparing it with the previously latched pulse value. CONSTITUTION:When the measurement of a detecting system 2 for fine detection is not reliable due to an overspeed or the like, first of all, a pulse value of the detecting system 2 latched by a latch circuit 17 in response to the first passage of a reference signal track 13 of another detecting system 3 for rough detection is stored in a storage circuit 18. Next, a main scale 6 and an index scale 7 both are relatively shifted toward an arrow A, and the pulse value of a pulse signal out of the detecting system 2 is counted by a counter circuit 16, while the latch circuit 17 reads the pulse value of the detecting system 2 in synchronizing with a light receiving signal 14 out of a light emitting element 8 in a corresponding position of the track 13 and feeds it to an arithmetic circuit 19, comparing it with the previously stored pulse value. Then, if a difference between these two pulse values is a value corresponding to a difference in the adjacent track 13, it is so judged that the detecting system 2 is performing a reliable measurement aright.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a measuring device for measuring the length, angle, angular velocity, etc. related to the relative movement of two members by an optical or magnetic method. In particular, the present invention relates to means for judging that measurement is impossible and issuing an alarm when the relative movement becomes faster than the detection capability of the detection means and becomes so-called overspeed.

[0002]

2. Description of the Related Art In a measuring device for measuring a length, an angle, etc. relating to a relative movement of two members, as a means for judging that the relative movement is overspeed faster than the detection capability of a detection means and cannot be measured. Conventionally, it is known that a counting circuit counts the pulses from the detecting means, and if the number of pulses per unit time is equal to or more than the set number, it is judged that measurement cannot be performed at an overspeed and an alarm is issued.

[0003]

In the conventional means for judging that relative movement is faster than the detection capability of the detection means and becomes overspeed and cannot be measured, the overspeed speed is secured to a larger value. In order to do so, the number of pulses per unit time set in the counting circuit is selected to be larger. However, in this case, even if the counter circuit is actually overspeeding and the counting circuit is miscounting, it cannot be determined that the relative movement is faster than the detection capability of the detection means and measurement cannot be performed, which causes a problem in reliability. ..

On the other hand, in order to obtain a high reliability in the determination that the relative movement detecting means cannot measure, the smaller the number of pulses set in the counting circuit, the higher the reliability becomes. .. However, if the number of pulses set in the counting circuit is made smaller, the detection capability relating to the speed of the detection means is further lost, and detection can be performed only when the relative movement speed is small. The problem arises. The present invention has been made in view of the above circumstances, and when determining that measurement is impossible due to a large relative movement speed and an excessive speed, the relative movement speed that is the overspeed is set. (EN) Provided is a measuring device which secures a larger size and has a high reliability of determination that measurement is impossible.

[0005]

SUMMARY OF THE INVENTION According to the present invention, a latch circuit synchronizes with a signal of a second detection system which performs a relatively coarse detection, and outputs a signal of a first detection system which performs a relatively dense detection. It is a measuring device configured to latch and determine whether or not the measurement is impossible based on the value of the pulse related to the preceding latch and the value of the pulse related to the current latch. ..

The detailed construction is such that a first detection system interposed between two members which move relative to each other, which performs a relatively dense detection, and outputs a pulse signal corresponding to the amount of the relative movement, and a first detection system. A second detection system that performs rough detection and outputs a signal corresponding to the amount of relative movement, and a calculation unit that calculates the amount related to relative movement based on the pulse signal from the first detection system are provided. The computing means includes a counting circuit that counts the pulse value of the pulse signal from the first detection system, and a first detection obtained through the counting circuit in synchronization with the signal from the second detection system. A latch circuit that reads the pulse value of the pulse signal from the system, a memory circuit that stores the pulse value of the pulse signal from the first detection system that is read into the latch circuit, and a signal from the counting circuit Calculate and calculate the amount related to relative movement , And the detection of the first detection system related to the current latch based on the value of the pulse of the signal read from the first detection system into the latch circuit and the value of the pulse related to the preceding latch stored in the storage circuit. It is a measuring device provided with an arithmetic circuit for determining whether or not it is reliable.

[0007]

The function of determining whether or not the measurement is impossible at an excessive speed is synchronized with the signal of the second detection system which performs a relatively rough detection, and is relatively dense captured by the latch circuit. The detection is performed based on the signal of the first detection system that performs detection.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on the embodiments shown in FIGS. However, the present invention is not limited to this embodiment. As shown in FIG. 1, the measuring device 1 is interposed between two members (not shown) that move relative to each other, and has a first detection system 2 that performs a relatively rough detection and a second detection system that performs a relatively rough detection. The detection system 3 and the calculation means 4 for calculating the amount related to the relative movement based on the pulse signal from the first detection system 2.

The first detection system 2 includes a main scale 6 provided with a main track 5, an index scale 7, a light emitting element 8, light receiving elements 9 and 10, and light receiving elements 9 and 10.
It is composed of a conversion circuit 11 for converting the sine wave from to a rectangular wave and a division circuit 12 for dividing the rectangular wave from the conversion circuit 11 into a predetermined width, and performs relatively dense detection to determine the amount of relative movement. The corresponding pulse signal is output. still,
The main scale 6 and the index scale 7 are attached to one side and the other side of the above-mentioned two members, respectively, and relatively move in the arrow A direction.

The second detection system 3 quadratures the waveforms of signals from the main scale 6 provided with a plurality of reference signal tracks 13, the index scale 7, the light emitting element 8, the light receiving element 14, and the light receiving element 14. It is composed of a waveform shaping circuit 15 for adjusting the shape, and performs a relatively rough detection and outputs a pulse signal corresponding to the amount of relative movement.
The plurality of reference signal tracks 13 are arranged on the main scale 6 at regular intervals. The calculation means 4 is composed of a counting circuit 16, a latch circuit 17, a storage circuit 18, a calculation circuit 19 and a CPU 20, and calculates the amount related to the relative movement based on the pulse signal from the first detection system 2. is there.

The counting circuit 16 counts the pulse value of the pulse signal from the first detection system 2. The latch circuit 17 reads the pulse value of the pulse signal from the first detection system 2 obtained via the counting circuit 16 in synchronization with the pulse signal from the second detection system 3. Memory circuit 1
Reference numeral 8 stores the value of the pulse of the pulse signal from the first detection system 2 read by the latch circuit 17. The arithmetic circuit 19 arithmetically processes the signal from the counting circuit 18 to calculate the amount related to the relative movement, and at the same time, stores the pulse value of the pulse signal from the first detection system 2 read by the latch circuit 17 and the storage circuit. The first detection system 2 relating to the current latch based on the value of the pulse relating to the preceding latch stored in 18.
The determination is whether or not the detection of is reliable.

The CPU 20 performs control by interposing between the circuits in the calculating means 4. The calculation means 4 is
When the CPU 20 judges that the detection of the first detection system 3 is unreliable, a signal indicating the amount related to the relative movement obtained by the calculation of the calculation unit 4 is displayed on the display unit 21, and a signal indicating that is issued as an alarm. It is configured to output to each means 22. Further, the arithmetic means 4 is configured to input a predetermined operation signal to the CPU 20 from the outside, such as resetting and deactivating the alarm means 22.

The measuring device 1 is constructed as described above. Therefore, when the main scale 6 and the index scale 7 relatively move in the direction of arrow A, the first detection system 2 operates and sends a pulse signal to the arithmetic means 4. That is, when light is emitted from the light emitting element 8 while the main scale 6 and the index scale 7 are relatively moving in the arrow A direction, the light reaches the light receiving elements 9 and 10 via the main scale 6 and the index scale 7. Then, the light receiving elements 9 and 10 send a sine wave signal to the conversion circuit 11 corresponding to the received light. The conversion circuit 11 converts the sine wave signal into a rectangular wave signal and sends the rectangular wave signal to the division circuit 12, and the division circuit 12 divides the rectangular wave signal from the conversion circuit 11 into a signal having a predetermined pulse width for calculation. It is sent to the counting circuit 16 of the means 4.

Here, the counting circuit 16 of the calculating means 4 counts the pulse value of the pulse signal from the first detection system 2 and sends the value to the CPU 20. The CPU 20 has a counting circuit 16
When it receives the value from, the value is sent to the arithmetic circuit 19 to calculate the amount of relative movement between the main scale 6 and the index scale 7, and the calculation result is sent to the display means 21 to be displayed on the display means 21. In the measuring means 1, when the measurement of the first measuring system 2 is unreliable due to overspeed or the like and the measurement is impossible, the second measuring system 3 and the calculating means 4 operate. Then an alarm is issued. That is, in the initial stage, the CPU 20 causes the storage circuit 18 to store the value of the corresponding pulse of the first measurement system 2 latched by the first passage of the reference signal track 13 in the second detection system 3. It works. Next, when the main scale 6 and the index scale 7 are moved relative to each other in the direction of arrow A, the pulse signal emitted from the first measuring system 2 reaches the counting circuit 16 and the pulse value is counted, and the value is latched by the latch circuit 17. Are continuously sent to.

On the other hand, due to the relative movement of the main scale 6 and the index scale 7 in the direction of arrow A, the light emitted from the light emitting element 8 at the corresponding position of the reference signal track 13 passes through the main scale 6 and the index scale 7 and the light receiving element. 14, the light receiving element 14 sends a signal to the waveform shaping circuit 15. The waveform shaping circuit 15 is the waveform shaping circuit 1.
The signal from 5 is shaped into a rectangular waveform and the latch circuit 17
Send to. Here, when the latch circuit 17 receives the signal from the waveform shaping circuit 15, the pulse value of the pulse signal related to the first detection system 2 from the counting circuit 16 is read in synchronization with the reception of this signal and the value is read. To the CPU 20. CPU
20 receives the value of the pulse from the latch circuit 17 and sends it to the arithmetic circuit 19, and calls the value of the pulse relating to the preceding latch from the memory circuit 18 to the arithmetic circuit 19 to compare the values of these two pulses.

Here, the arithmetic circuit 19 includes the first detection system 2
The current pulse value and the preceding pulse value are compared for the pulse signal related to. In the comparison, if the difference between the two values is a value corresponding to the difference between the adjacent reference signal tracks 13, the arithmetic circuit 19 determines that the first detection system 2 is performing reliable detection, and informs that effect. The signal is sent to the CPU 20. The CPU 20 continues to operate so that the value obtained based on the detection of the first detection system 2 is displayed on the display means 21 as the amount of relative movement between the main scale 6 and the index scale 7. The measurer receives that the measurement of the measuring device 1 is being performed correctly, and continues the desired measurement.

When the main scale 6 and the index scale 7 reversely move in the middle, and the second reference system 13 continuously passes through the same reference signal track 13 in the second measuring system 3, the CPU 20 causes the CPU 20 to move. , Operates to cause the arithmetic circuit 19 to determine whether the difference between the values of the two pulses of the preceding latch and the current latch is zero. If the difference is zero, the arithmetic circuit 19 determines that reliable detection is performed. When the arithmetic circuit 19 finishes comparing the values of the two pulses of the preceding latch and the current latch, CP
U20 operates so that the value of the pulse related to the current latch becomes the value of the pulse related to the preceding latch and the storage circuit 18 stores the value.

On the other hand, if there is no constant difference in the comparison of the two pulse values, the arithmetic circuit 19 judges that the first detection system 2 is not performing reliable detection and informs the CPU 20 accordingly. Send by signal. The CPU 20 receives a signal from the arithmetic circuit 10 and sends an operation signal to the alarm means 22. The alarm means 22 receives a signal from the CPU 20 and operates to issue an alarm, whereby the measurer receives that the measurement of the measuring device 1 is not correctly performed, interrupts the measurement, and leaves the measuring device 1 in the initial state. Reset to and continue measurement. In FIG. 2, the alarm means 22 indicates that the detection of the detection system 2 of the measuring device 1 is not reliable and the measurement is impossible.
7 shows a flowchart relating to an alarm by the operation of.

The measuring device 1 determines whether or not the measurement is possible by determining whether or not the first detection system 2 is performing reliable detection due to overspeed, and a relatively rough detection is performed. Is performed based on the pulse signal of the first detection system 2 that performs relatively dense detection, which is captured by the latch circuit 17 in synchronism with the signal of the second detection system 3. It is highly reliable because it does not cause problems due to miscounting unlike the method used. Further, since it is not necessary to set the number of pulses to be small, the detection speed will not be impaired. Further, in the measuring device 1, not only due to overspeed, but when the detection of the first measuring system 2 is in an unreliable state, the second measuring system 3 and the calculating means 4 operate,
An alarm is issued.

In the measuring apparatus 1, a plurality of reference signal tracks 13 are arranged at regular intervals, and whether the detection of the first detection system 2 is reliable or not is judged by the value of the preceding pulse and the value of the current pulse. Is calculated based on the arithmetic circuit 19 performing an arithmetic operation. However, a plurality of reference signal tracks 13 are arranged so that adjacent intervals are respectively set to desired intervals, pulse values are obtained based on the respective intervals, and the pulse values are adjacently preceded. The difference with respect to the pulse value is stored in the storage circuit 18,
The determination as to whether the detection of the first detection system 2 is reliable is performed by calculating whether the difference between the value of the preceding pulse and the value of the current pulse is equal to the difference between the corresponding pulses stored in the memory circuit 18. The configuration may be performed based on the calculation by the circuit 19.

In this configuration, when the main scale 6 and the index scale 7 reversely move in the direction of relative movement, when the second measuring system 3 continuously passes through the same reference signal track 13. The CPU 20 causes the arithmetic circuit 19 to determine whether the difference between the values of the two pulses of the preceding latch and the current latch is zero. The measuring device 1 measures the distance when the relative movement is performed, but may be the one that measures the relative movement speed, angle, angular velocity, or the like. The measuring device 1 is configured to optically detect the relative movement, but may be configured to magnetically detect the relative movement.

[0022]

As described above, according to the present invention, the signal of the first detection system for performing the relatively dense detection is latched in synchronization with the signal of the second detection system for performing the relatively coarse detection, and the preceding latch is used. Based on the comparison of the value of the pulse related to the value of the pulse related to the current latch, it is configured to judge whether the detection of the first detection system is reliable or not. When it is determined that measurement is impossible due to overspeed because it becomes larger than a predetermined value, a larger relative speed of overspeed is secured, and the determination of measurement failure is highly reliable. It is a measuring device. Further, the present invention is not limited to the reason that the measurement is impossible in the state of the overspeed in which the speed of the relative movement is higher than a predetermined value.

[Brief description of drawings]

FIG. 1 is a structural explanatory view showing an embodiment of the present invention.

FIG. 2 is a flowchart showing an operation sequence of main parts of the embodiment shown in FIG.

[Explanation of symbols]

 1; Measuring device 2; First measuring system 3; Second measuring system 4; Arithmetic means 6; Main scale 7; Index scale 16; Count circuit 17; Latch circuit 19; Arithmetic circuit 22; Alarm means

Claims (1)

[Claims] 1. A first detection system, which is interposed between two members that move relative to each other, performs a relatively dense detection and outputs a pulse signal corresponding to the amount of the relative movement, and a relatively coarse detection. A second detection system that outputs a signal corresponding to the amount of the relative movement and a calculation unit that calculates the amount related to the relative movement based on the pulse signal from the first detection system are provided. Is a counting circuit for counting the value of the pulse of the pulse signal from the first detection system, and the pulse from the first detection system obtained through the counting circuit in synchronization with the signal from the second detection system. A latch circuit that reads the value of the pulse of the signal,
A storage circuit that stores the pulse value of the pulse signal from the first detection system that is read into the latch circuit, and calculates the amount related to relative movement by calculating the signal from the counting circuit and reading into the latch circuit. Whether the detection of the first detection system related to the current latch is reliable based on the value of the pulse of the signal from the first detection system and the value of the pulse related to the preceding latch stored in the memory circuit. A measuring device provided with an arithmetic circuit for making a judgment.