JPH06265563A - Moving speed detector for encoder - Google Patents

Abstract

PURPOSE:To provide a moving speed detector for encoder in which error in the speed signal is not affected even if a mobile moves at high speed. CONSTITUTION:Count is read out immediately before a pulse counter 5 is reset by a reset signal delivered from a preset counter 3. An operating circuit 6 adds the number epsilon of error pulses to the count thus read out operates the moving speed Vn of an encoder which is delivered, as a digital signal, to a D/A converter 7 and converted into an analog signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is an encoder for detecting the position or angle of an object to be measured and generating a pulse corresponding to the detected position or angle.
The present invention relates to a moving speed detection device for an encoder that detects the moving speed of the encoder.

[0002]

2. Description of the Related Art A position detecting encoder is widely known as a device for detecting the position of a moving body. Then, it is required to obtain the moving speed of the moving body based on the pulse signal output from the position detecting encoder.

[0003]

Therefore, the pulse signal output from the position detecting encoder is taken into the microcomputer and a reset signal is generated every time the microcomputer moves a predetermined distance within the microcomputer. A speed counting counter that repeats pulse counting each time the reset signal is input is provided, and the moving speed of the moving body is obtained by dividing the predetermined distance by the count value of the speed counting counter.

However, if the moving body is moving at high speed,
The count value counted by the speed counting counter becomes smaller by the time the moving body moves a predetermined distance. Also, there is a delay time from the reset of the speed counting counter to the actual start of the counting operation. Due to the delay time, the count value immediately before the speed counting counter is reset is less than the actual value. Will be counted.

Here, when the speed of the moving body is low, the count value of the speed counting counter is sufficiently larger than the count value based on the number of error pulses, so there is no problem, but when the speed of the moving body becomes high, There is a problem in that the influence of the error pulse cannot be ignored and the error in the speed signal increases as the speed of the moving body increases. The same applies to the case where the angular velocity is calculated from the output of the angle detecting encoder as well as the position detecting encoder.

The present invention has been made in view of the above points, and an object thereof is to detect the moving speed of an encoder that does not affect the error of the speed signal even if the moving speed of the moving body becomes high. To provide a device.

[0007]

SUMMARY OF THE INVENTION The present invention comprises an encoder for outputting a measuring pulse for each unit distance or unit angle, and a counting means for counting the measuring pulse and outputting a reset signal at a predetermined distance or angle. A reference pulse generator that generates a reference pulse, a reference pulse counting means that counts the reference pulse and is reset by a reset signal output from the counting means, and a reference pulse by the reset signal output from the counting means The count value immediately before the counting means is reset is read, the error pulse number is added to the count value, the moving speed of the encoder is calculated and output as a digital signal, and the digital signal from the calculating means. And a D / A converter for converting the signal into an analog signal.

[0008]

The count value immediately before the reference pulse counting means is reset by the reset signal output from the counting means is read, and the error pulse number is added to the count value.
The moving speed of the encoder is calculated and output as a digital signal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An encoder moving speed detecting apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a schematic structure of a moving speed detecting device of an encoder, and FIG. 2 is a timing diagram for explaining the operation.

In FIG. 1, reference numeral 1 denotes a position detecting encoder for detecting the screw position after injection molding, for example. The position detecting encoder 1 outputs only one position data pulse each time the screw moves a unit distance. The position data pulse output from the position detecting encoder 1 is input to the controller 2.

That is, the position data pulse is input to the preset counter 3 in the controller 2. The preset counter 3 is set with the number of pulses generated by the encoder 1 moving by a predetermined distance .DELTA.L as shown in FIG. 2, and the number of pulses is input from the encoder 1. And a reset signal is output to the reference pulse counter 5. Reference numeral 4 is a reference pulse generating circuit that outputs a BHz reference pulse signal. The cycle of this reference pulse signal is Δt as shown in FIG.

The reference pulse signal output from the reference pulse generating circuit 4 is input to the reference pulse counter 5. The reference pulse counter 5 counts the reference pulses output from the reference pulse generating circuit 4, and counts the reference pulses from the input of the reset signal from the preset counter 3 to the input of the next reset signal.

Therefore, the count value just before the reference pulse counter 5 is reset is the number of reference pulses required for the encoder 1 to move by the predetermined distance ΔL, in other words, the moving time (t ₁ , t ₂ , t in FIG. 2). ₃ , t _n ).

While the reference pulse counter 5 is reset by the reset signal from the preset counter 3, a delay time td is generated as shown in FIG. Then, due to the delay time td, the error pulse number ε which is not counted is generated in the reference pulse counter 5. The number of error pulses is constant in all cases.

The output of the reference pulse counter 5 is output to the arithmetic circuit 6. The arithmetic circuit 6 is the reference pulse counter 5
Is about to be reset (C ₁ in Fig. 2,
At the same time as reading C ₂ , C ₃ , C _n ), a reset signal for resetting the reference pulse counter 5 is output.

Then, the arithmetic circuit 6 uses the count value C _n of the reference pulse counter 5 as the error pulse number ε as shown in FIG.
Is added to obtain a count value C _n ′, and the moving speed V _n of the encoder 1 is calculated from the equation (1). V _n = ΔL / (Δt · C _n ′) (1)

Then, the arithmetic circuit 6 outputs a digital signal of the moving speed of the encoder 1 to the D / A converter 7.
The D / A converter 7 converts the pulse from the arithmetic circuit 6 and outputs it as an analog signal of the moving speed of the encoder 1.

Next, the operation of the embodiment of the present invention constructed as above will be described. First, when the moving body moves, the encoder 1 outputs a position data pulse to the preset counter 3. The preset counter 3 counts the pulses from the encoder 1 and, when counting the number of pulses corresponding to a predetermined distance ΔL, outputs a reset signal to the reference pulse counter 5 and counts the pulses again.

The reference pulse counter 5 counts the reference pulse signal output from the reference pulse generating circuit 4 between the reset signal output from the preset counter 3 and the next reset signal. The arithmetic circuit 6 resets the reference pulse counter 5 after reading the count value C _n just before the reference pulse counter 5 is reset.

[0020] Then, the arithmetic circuit 6 and the count value C _n 'by adding the error pulse number ε to the count value C _n, diene from the aforementioned (1) - calculates the movement velocity V _n da 1.

By the way, reading of the count value C _n of the reference pulse counter 5 and the reference pulse counter 5
Is reset each time the reset signal of the preset counter 3 is output. At this time, the delay time td in FIG.
As shown by, the count value C of the reference pulse pulse counter 5
Due to the delay of the reading of _n and the reset process, the error of the error pulse number ε always occurs with respect to the regular count value C _n . This error is low speed, but when the error pulse number ε is sufficiently small with respect to the count value C _n is negligible, because the speed is increased count value C _n is small, the error pulse number ε can not be ignored.

Therefore, although the actual count value C _n of the reference pulse counter 5 is actually C _n -ε, the error pulse number ε is set as C _n + ε considering that td is constant.
By canceling, the influence of the error pulse number ε can be eliminated.

Then, the moving speed V _n obtained by the arithmetic circuit 6 is output to the D / A converter 7. The D / A converter 7 converts a digital signal into an analog signal and outputs it as a moving speed signal of the encoder 1 to a predetermined device (not shown). In this way, it is possible to calculate a highly accurate moving speed using an encoder without a special additional circuit. The configuration of the controller 2 of the above embodiment may be replaced with a one-chip microprocessor 8 as shown in FIG.

[0024]

As described above in detail, according to the present invention, there is provided an encoder moving speed detecting device which does not affect the error of the speed signal even if the moving speed of the moving body becomes high. can do.

[Brief description of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a moving speed detecting device for an encoder according to an embodiment of the present invention.

FIG. 2 is a timing chart for explaining the operation of the embodiment.

FIG. 3 is a block diagram showing a modified example of the present invention.

[Explanation of symbols]

1 ... Position detection encoder, 2 ... Controller, 3 ... Preset counter, 4 ... Reference pulse generation circuit, 5 ... Reference pulse counter, 6 ... Arithmetic circuit, 7 ... D / A converter
Ta.

Claims (1)

[Claims] 1. An encoder for outputting a measurement pulse for each unit distance or unit angle, a counting means for counting the measurement pulse and outputting a reset signal at a predetermined distance or angle, and a reference for generating a reference pulse. Immediately before the reference pulse counting means is reset by a pulse generator, a reference pulse counting means that counts the reference pulse and is reset by a reset signal output from the counting means, and a reset signal output by the counting means. After reading the count value of and adding the error pulse number to the count value,
An encoder characterized in that it comprises a computing means for computing the moving speed of the encoder and outputting it as a digital signal, and a D / A converter for converting the digital signal from the computing means into an analog signal. Mobile speed detector.