JPH08247788A - Rotary encoder receiving circuit - Google Patents

Abstract

(57) [Summary] [Object] The present invention reduces the output signal line of an encoder,
It is an object of the present invention to provide a highly reliable AC servo driver with high productivity and stable signal reception and signal reproduction of each signal output. [Structure] Serial-to-parallel converter 11 for receiving serial data and converting it into parallel data, count data and C
A data latch circuit 12 for latching the S1, CS2, CS3 phases and Z state information, a BRM circuit 15 for generating a reproduction timing pulse for reproduction in the A, B2 phases, a frequency setting circuit 16 for determining an output frequency, Reproduction pulse number counter 17 for counting the number of reproduction timing pulses
And a 90 degree phase difference A based on the playback timing pulse
The pulse reproduction circuit 18 converts the / B phase and the reference signal Z phase during one rotation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotary encoder data receiving circuit for detecting the rotational position of a rotating body, and in particular, this receiving circuit is used for servo processing of an AC servo driver compatible with an incremental encoder. It is what is done.

[0002]

2. Description of the Prior Art Servo motors used for driving various machines include DC servo motors with brushes and brushless A servo motors.
There are C servo motors (DC brushless servo motors), and in recent years, rotary encoders incorporated and used in servo motors have become widespread. Encoders incorporated in AC servomotors are roughly classified into incremental encoders and absolute encoders. Incremental encoders are widely used by being attached to AC servo motors of various machines and occupy the mainstream as AC servo encoders. On the other hand, an absolute encoder is an encoder that can determine the absolute position within one revolution.
It is widely used in servo motors for large robots such as multi-joint robots because it does not require home-return operation.

A conventional incremental encoder and encoder receiving circuit will be described below with reference to FIG.

The encoder output unit 91 has A and B phase signals having a 90-degree phase difference and an origin reference Z of one pulse per rotation.
Signals and commutation signals CS1, CS2, CS3
Is output from the signal transmitting circuit 92, and the servo driver input unit 93 causes the signal receiving circuit 94 to output the A and B phase signals, Z.
The signals CS1, CS2 and CS3 are directly received in parallel and used for servo processing.

[0005]

However, in the above-mentioned conventional structure, since the number of output signals is large and the number of wirings is large, mass productivity is poor, and erroneous wiring to equipment and disconnection of the signal line itself are likely to occur. There was a point.

The present invention solves the above-mentioned problems of the prior art by eliminating the number of signal lines by transmitting a signal in serial data, and after receiving serial data, A, B, Z, C.
It is an object of the present invention to provide an AC servo driver having both mass productivity and reliability by easily reproducing S1, CS2, CS3.

[0007]

In order to achieve this object, an incremental encoder receiving circuit of the present invention receives serial data transmitted from a rotary encoder and has A and B two phases having a 90-degree phase difference from each other. Parallel conversion of the count data counted according to the phase, the phase excitation switching signals (commutation signals) CS1, CS2, CS3 phases of the three-phase AC servo motor, and the state information of the reference signal Z indicating the origin during one rotation. Serial-parallel converter, a data latch circuit for latching the count data from the serial-parallel converter and the CS1, CS2, CS3 phases and Z state information, and a reproduction for reproducing the A and B2 phases with a 90-degree phase difference. BRM circuit for generating timing pulse and frequency for determining output frequency of the BRM circuit A constant circuit, wherein a reproduced pulse number counter for counting the number of reproduction timing pulses, a 90 degree phase difference based on the reproduction timing pulse A, B2
Phase and a pulse reproduction circuit for converting into a reference signal Z phase during one rotation.

[0008]

With this configuration, A, B, Z, CS1, CS
Since the signals of the 2nd and 3rd CS phases can be transmitted on one line as serial data, the number of input signals of the AC servo driver can be reduced, and A, B, Z, CS1, CS2, and CS3 can be easily reproduced, which is excellent in mass productivity. A highly reliable AC servo driver can be obtained.

[0009]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram of an encoder receiving circuit according to an embodiment of the present invention. In FIG. 1, 11 is a serial-parallel converter, 12 is a data latch circuit, 13 is a microprocessor, 14 is a gate circuit, 15 is a BRM circuit,
16 is a frequency setting circuit, 17 is a reproduction pulse number counter,
Reference numeral 18 is a pulse reproduction circuit.

FIG. 2A shows an operation waveform example of the up / down counter of the rotary encoder on the transmission side. Here, an operation example of the 16-bit counter is shown.

FIG. 2B shows an example of the entire operation waveform of the up / down counter of the rotary encoder on the transmission side.

FIG. 3 is a configuration diagram of serial data input to the serial / parallel conversion unit 11. One frame of data is composed of a start bit, a mode bit, a data bit, a parity bit, a stop bit, an idle bit and the like. The interrupt signal input to the microprocessor 13 is generated in synchronization with the frame of serial data.

FIG. 4 shows Z-phase state information in the serial data sent from the rotary encoder on the transmission side. A, B, and
It is a representation of Z-phase state information when the Z-phase changes.

FIG. 5 shows an example of the configuration of the pulse reproduction circuit 18, which is an A / B phase reproduction circuit 51, a Z phase initialization circuit 52, A.
It is composed of a phase-one rotation counter circuit 53.

FIG. 6 shows an example of the A / B phase reproduction operation waveform. The initial setting operation of the A / B phase is performed only once when the power is turned on, and the A and B2 phase outputs are performed for each subsequent frame. It is being shown.

FIG. 7 shows an example of the Z-phase reproduction operation waveform, and shows that the Z-phase is output by the A-phase one-revolution counter circuit 53 after the Z-output request signal is set.

FIG. 8 is an operation flowchart of the microprocessor according to the embodiment of the present invention.

The operation of the rotary encoder receiving circuit configured as described above will be described. First, data for performing pulse reproduction is transmitted as serial data from the rotary encoder. For example, in Figure 2.
When the power is turned on as shown in (a), the encoder side sets the initial value "3" by the current signal level detection of the A and B2 phases, and when the axis rotates to CW, 3 → 2 → 1 → 0 → 6.
5535, and thereafter, the counter operates as a cyclic counter as shown in FIG. 2B, and the current count value is set as A / B phase count data information (D0 to D15) for each frame of serial data on the receiving side. To transmit.

The Z-phase state information (Z1, Z0) is determined by the Z-phase change of each frame of serial data, Z1 represents the Z state one frame before, and Z0 represents the Z state of the current frame. It represents. For example, in FIG.
At the h point, the Z phase is “L”, so that Z1 and Z0 are 0,0, at the i point, the Z phase is “H”, Z1 and Z0 are 0 and 1, and at the j point, the Z phase is “H” and therefore Z1. , Z0 is 1,1 and at the point k, the Z phase is “L”, so Z1, Z0 are 1,0. Figure 4 (b)
Is "L" in Z phase within one frame from m point to n point
→ "H" → "L", so Z1, Z at n point
0 is 0,1 and Z1 and Z0 at the o point are 1,0.

Next, the serial data from the rotary encoder is sent to the receiving side with the structure shown in FIG. The output cycle of this serial data is transmitted at a speed twice or more the electric time constant of the motor to be controlled. In this way, from the rotary encoder, A / in FIGS.
B-phase count data and Z in FIGS. 4 (a) and 4 (b)
The phase state information is repeatedly transferred to the receiving circuit side every predetermined time by the structure of serial data shown in FIG.

Next, the operation of A / B phase reproduction will be described with reference to FIG. A / detected by rotary encoder
The B-phase count data is sequentially input as serial data (RXD) to the serial / parallel conversion unit 11, and after all bits are input, it is sent to the data latch circuit 12. When the data latch circuit 12 completes the latching, it issues the interrupt request signal of FIG. 6 to the microprocessor 13. The microprocessor 13 reads the transmitted A / B phase count data from the data latch circuit 12 in the interrupt processing program. If the interrupt processing program is the first time after the main power is turned on, the A phase output and the B phase output are output to the pulse reproduction circuit 18 from the information of the lower 2 bits (D1, D0) of the current A / B phase count data. An A / B phase initial latch signal is output as a latch signal for initial setting. Further, from the second time onward, the microprocessor 13 obtains a difference pulse between the A / B phase count data at the time of the previous interruption and the current A / B phase count data, and writes the difference pulse to the reproduction pulse number counter 17 and the frequency setting circuit 16. At the same time, it outputs a pulse reproduction direction (motor rotation direction) signal to the pulse reproduction circuit 18, and then outputs a reproduction pulse start signal to the gate circuit 14. The gate circuit 14 uses the reference clock BR
A clock is output to the M circuit 15, and the BRM circuit 15 outputs a reproduction timing pulse based on the input clock and the frequency determined by the frequency setting circuit 16. The pulse reproduction circuit 18 determines the A-phase output and the B-phase output based on the preset pulse reproduction direction signal at the timing of the reproduction timing pulse. At the same time, the reproduction timing pulse is input to the reproduction pulse number counter 17. Playback pulse counter 17
When the number of reproduction pulses is down-counted and zero is detected, a pulse reproduction completion signal is output to the gate circuit 14 and the clock output to the BRM circuit 15 is stopped.

By repeating the above operation, the A phase and the B phase
The phase is output continuously. Next, regarding Z-phase reproduction, FIG.
The operation will be described with reference to FIG. In the A / B phase reproduction operation, when Z1 and Z0 of the Z phase state information are 0 and 1 only after the main power is turned on, the Z output request signal is sent to the Z phase initial setting circuit 52 in the pulse reproduction circuit 18. Is output. Z
The phase initializing circuit 52 detects the edge of the A phase output generated by the A / B phase reproducing circuit 51 and synchronizes with the next pulse of “L” → “H” → “L” of the Z phase and the Z phase. Is output. Further, the count value of the A-phase one-revolution counter circuit 53 is cleared to zero by the Z-phase output pulse output by the Z-phase initial setting circuit. The counter of the A-phase one-revolution counter circuit 53 inputs the A-phase output of the A / B-phase regeneration circuit 51, and counts up / down (the resolution pulse number of one revolution of the encoder) preset by the microprocessor 13 ( During CCW rotation, up-counting by A phase rising edge detection, during CW rotation,
The A phase falling edge is detected and the zero count signal is output by detecting zero, and the Z phase is synchronized with the A phase "L" → "H" → "L" pulse. Output.

As described above, the Z-phase position is stored in the A-phase single-revolution counter circuit 53 from the microprocessor 13 only once after the main power is turned ON, so that the Z-phase can be generated without being managed by the microprocessor 13 thereafter. It will be possible.

Next, a flowchart of the operation of the microprocessor 13 is shown in FIG. The reproduction operation of the A and B2 phases and the Z phase reproduction operation are performed based on the flowchart of the microprocessor 13 of FIG.

Further, in the Z-phase reproduction operation, in the frame in which Z1, Z0 of the Z-phase state information is detected as 0, 1 for the first time, if the rotation speed of the motor is high, the A / B phase in the previous interruption (frame) is detected. The difference pulse number (reproduction pulse) between the count data and the A / B phase count data at this interrupt (frame) may become large, and the original output timing of the Z phase in the reproduction pulse may be displaced. Therefore, each time the microprocessor 13 detects Z1, Z0 of the Z-phase state information 0, 1, whether the difference pulse number is smaller than that when Z1, Z0 of the Z-phase state information previously detected 0, 1 or not. If it is smaller this time, the Z output request signal is output to the Z phase initial setting circuit 52 in the pulse reproduction circuit 18. As a result, the count value of the A-phase single rotation counter circuit 53 is cleared again,
Since the Z-phase position is re-stored, it is possible to output Z-phase without deviation.

With the above configuration, the signal line can be made into one line by serially transmitting A / B phase count data, commutation data, Z phase status information, etc.
Builds an AC servo driver that can reduce the wiring man-hours of the equipment and improve the reliability against the disconnection of the signal line and can accurately reproduce the original A, B2 phase and Z phase after receiving the serial data. it can.

[0028]

As described above, according to the present invention, A, B, Z, C
By transmitting the S1, CS2, and CS3 signals as serial data, the number of signal lines that was conventionally required to be 14 can be reduced to 4, and after receiving serial data, A, B, Z, CS1, CS2, CS
AC that can easily reproduce 3 and has mass productivity and reliability
Servo driver can be realized.

[Brief description of drawings]

FIG. 1 is an encoder reception circuit diagram according to an embodiment of the present invention.

FIG. 2 is an operation waveform diagram of an up / down counter of a transmission side rotary encoder according to an embodiment of the present invention.

FIG. 3 is a configuration diagram of serial data according to an embodiment of the present invention.

FIG. 4 is a Z-phase state information operation waveform diagram in one embodiment of the present invention.

FIG. 5 is a pulse regeneration circuit diagram according to an embodiment of the present invention.

FIG. 6 is a waveform diagram of A / B phase reproduction operation according to an embodiment of the present invention.

FIG. 7 is a Z-phase reproduction operation waveform diagram in one embodiment of the present invention.

FIG. 8 is a flowchart of the microprocessor operation in one embodiment of the present invention.

FIG. 9 is a transmission / reception configuration diagram of a conventional rotary encoder and a rotary encoder receiving circuit.

[Explanation of symbols]

 11 serial-parallel converter 12 data latch circuit 13 microprocessor 14 gate circuit 15 BRM circuit 16 frequency setting circuit 17 reproduction pulse number counter 18 pulse reproduction circuit 51 A / B phase reproduction circuit 52 Z phase initial setting circuit 53 A phase one rotation counter Circuit 91 Encoder output unit 92 Signal transmission circuit 93 Servo driver input unit 94 Signal reception circuit

Claims (4)

[Claims] 1. Count data obtained by receiving serial data transmitted from a rotary encoder and counting the phases of A and B2 phases having a 90-degree phase difference with each other, and a phase excitation switching signal of a three-phase AC servomotor. (Commutation signal) CS1, CS2, CS3 phases and a serial / parallel conversion unit for performing parallel conversion to the status information of the reference signal Z indicating the origin during one rotation, count data from the serial / parallel conversion unit, and CS1, CS2 ，
A data latch circuit for latching the CS3 phase and Z phase state information, a BRM circuit for generating a reproduction timing pulse for reproducing the A and B2 phases having a phase difference of 90 degrees, and the BRM.
A frequency setting circuit that determines the output frequency of the circuit, a reproduction pulse number counter that counts the number of the reproduction timing pulses, and A and B two-phases having a 90-degree phase difference based on the reproduction timing pulses and a reference signal Z during one rotation. A rotary encoder receiving circuit having a pulse regeneration circuit for converting into a phase. 2. An A / B phase regeneration circuit for determining the levels of the A phase and B phase with a 90 degree phase difference based on the reproduction pulse timing, and the A phase and the input signal generated by the A / B phase regeneration circuit. A Z-phase initialization circuit that initializes the Z-phase in response to a Z-output request signal that is given, and a counter operation that moves up and down the N-ary by detecting a change edge of the A-phase after the count is cleared by the Z-phase initialization circuit. The rotary encoder receiving circuit according to claim 1, further comprising a pulse regeneration circuit including an A-phase one-revolution counter circuit that determines the level of the Z-phase signal at the timing when the count values are zero-matched. 3. A data latch circuit, the frequency setting circuit, the reproduction pulse number counter, and the pulse reproduction circuit,
It has a bus connection with a microprocessor (CPU),
Each time the serial data is received, the difference between the A / B phase count data at the previous sampling and the A / B phase count data at the current sampling is applied to the reproduction pulse number counter and the frequency setting circuit. Write the number of B phase reproduction pulses and
The Z-phase generation timing is initialized in the pulse reproduction circuit based on the phase state information, and after the initialization, the level of the Z-phase signal is determined by the zero coincidence of the A-phase single-revolution counter circuit. Claim 1 or Claim 2
The described rotary encoder receiving circuit. 4. When sampling the serial data is received, if the Z-phase of the Z-phase status information detects that the Z-phase is active, the number of A / B-phase reproduction pulses and the current A / B when the Z-phase active was previously detected. The number of B-phase reproduction pulses is compared, and if the number of A / B-phase reproduction pulses is smaller this time, the Z-phase generation timing is initialized again. The described rotary encoder receiving circuit.