JP2540177B2 - Servo motor signal transmission equipment - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a signal transmission device of a servo motor for transmitting various signals from a synchronous servo motor to a servo driver via a transmission path.

<Prior Art> FIG. 5 shows a specific example of a conventional signal transmission device of this kind, and FIG. 6 shows a time chart thereof, in which a servo motor 1 and a servo driver 2 are connected via a transmission line 3. Connected to each other.

The servo motor 1 incorporates a pole sensor 5 and a rotary encoder 6 mechanically coupled to the motor body 4, and also incorporates a temperature sensor 8 for detecting a temperature abnormality of the transmission circuit unit 7 and the servo motor 1. The transmission circuit unit 7 includes magnetic pole position detection signals Pu, Pv, Pw of the pole sensor 5.
Three line drivers 9 for transmitting (hereinafter, referred to as "Pu phase signal", "Pv phase signal", and "Pw phase signal") and Z phase, A phase, and B phase signals Z of the rotary encoder 6. , A, B (hereinafter, referred to as “Z-phase signal”, “A-phase signal” and “B-phase signal”), and three line drivers 10 for transmitting the line drivers 9, 10 and the servo driver. Signal lines 14 to 25 for signals forming a balanced transmission line are connected to the line receivers 12 and 13 of the receiving circuit unit 11 in FIG.

The transmission line 3 includes signals of Pu phase, Pv phase, and Pw phase + Pu, −P
6 signal lines for transmitting u, + Pv, -Pv, + Pw, -Pw 1
4 to 19 and each signal of Z phase, A phase, B phase + Z, -Z, + A, -A, + B,
-Six signal lines 20 to 25 for transmitting B, two signal lines 26 and 27 for transmitting sensor signals TH ₁ and TH ₂ by the temperature sensor 8, and voltages of +5 V and 0 V And signal lines 28 to 30 for supplying the ground GND, and these 17 signal lines are provided for a required distance. In the figure, R, S, T, E indicate a three-phase AC power supply.

<Problems to be Solved by the Invention> However, in the above device example, the number of signal lines is large and the connection work is complicated because the balanced transmission line is adopted as the signal transmission method. Moreover, since the number of signal lines is large, the diameter of each signal line cannot be increased, and the probability of an accident due to disconnection becomes high. In addition, there are many problems such as an increase in system cost because the cost of parts such as connection cables and connectors and the labor cost required for connection work increase.

By the way, the rotary encoder 6 is now 10
Assuming that the A-phase and B-phase signals of 00 pulses are output and the servo motor 1 rotates at 3600 [rpm], the A-phase,
The frequency of each B-phase signal is 60 [KHz]. In addition, the phase difference time between the A-phase signal and the B-phase signal at this time is 2.5 at the worst value.
It becomes about [μsec].

Thus, in order to reduce the number of signal lines in the transmission line 3, it is conceivable that the transmission signal is serially transmitted. However, when this transmission system is introduced into this kind of device, in the above example, within 2.5 [μsec] time. It is necessary to send out all the signals, and a very high transmission rate is required.

Therefore, the inventor of the present invention has found that a signal whose transmission time hardly causes a problem, that is, P output by the pole sensor 5
Focusing on each of the u, Pv, Pw phase signals, the Z phase signal output by the rotary encoder 6, and the sensor signal output by the temperature sensor 8, first, the possibility of serial transmission of these signals was examined. .

First, considering each signal of the Pu, Pv, Pw phases, assuming that the number of magnetic poles of the servo motor 1 is 6 and the number of rotations of the servo motor 1 is 4000 [ram], the signals of the Pu, Pv, Pw phases are The electrical angle 2π is about 5 [msec]. If it is assumed that the magnetic pole detection accuracy is about 2 degrees, it is considered that there is no problem if the transmission time of each signal of the Pu, Pv, and Pw phases is about 27 [μsec] or less.

Next, the Z-phase signal of the rotary encoder 6 will be considered. This Z-phase signal is used to align the mechanical origin of the device, and it is necessary to reduce the rotation speed of the servo motor 1 in order to perform accurate alignment. Therefore, the rotation speed when adjusting the origin is 1/50 to 1/1 of the maximum rotation speed.
Set to 200. As a result, the practical speed is 400 [μsec] as the pulse width of the Z-phase signal, and it is considered that the transmission speed of each of the Pu, Pv, and Pw-phase signals is sufficient.

Finally, considering the sensor signal, this sensor signal does not cause a speed problem by its nature.

Therefore, according to the present invention, signals that are not required to be responsive in control, that is, signals of the Pu, Pv, and Pw phases by the pole sensor 5, Z phase signals by the rotary encoder 6, and sensor signals by the temperature sensor 8 are first converted into serial signals. Then
Then, by converting the serial signal and a signal having a high response speed into a serial signal and transmitting the serial signal, it is an object to provide a signal transmission device for a servo motor in which the number of signal lines and the transmission bit length are significantly reduced. To do.

<Means for Solving Problems> In order to achieve the above object, in the present invention, a servo driver including a pole sensor, a rotary encoder, and a motor abnormality detection sensor is connected to a servo driver via a transmission path. In the signal transmission device of the servo motor consisting of,
The servo motor receives a magnetic pole position detection signal output by a pole sensor, a Z-phase signal output by a rotary encoder, and a sensor signal output by a motor abnormality detection sensor, and converts the signal into a serial signal. A conversion circuit section, a second conversion circuit section for inputting the serial signal output from the first conversion circuit section and the A-phase signal and the B-phase signal output from the rotary encoder, and converting the serial signal into a serial signal; The transmission circuit section for transmitting the serial signal output from the second conversion circuit section to the transmission path is provided.

<Operation> In the device of the present invention, the magnetic pole position detection signal, the Z-phase signal, and the sensor signal are first converted into serial signals, and then the serial signals and the A-phase and B-phase signals are converted into serial signals for transmission. Therefore, not only a dedicated signal line for individually transmitting these signals becomes unnecessary, but also the signal lines for transmitting these signals can be integrated, and the number of signal lines can be significantly reduced. In addition, the bit length of signal transmission can be greatly reduced, and high-speed transmission becomes possible.

<Embodiment> FIG. 1 shows a signal transmission device for a servo motor according to an embodiment of the present invention, in which a transmission path 3 is formed between a servo motor 1 and a servo driver 2 by a plurality of signal lines. Has been done. The servo motor 1 includes a motor body 4
In addition to incorporating the pole sensor 5 and the rotary encoder 6 mechanically coupled to, an abnormality detecting sensor 31, first and second parallel / serial conversion circuits 32, 33, etc. are incorporated.

The pole sensor 5 is for detecting the magnetic pole position of the motor body 4, and is a three-phase magnetic pole position detection signal, that is,
The Pu phase signal, Pv phase signal, and Pw phase signal are output to the first parallel / serial conversion circuit 32. The rotary encoder 6 is of an incremental type, and the A-phase and B-phase signals are the second
Is output to the parallel / serial conversion circuit 33, and the Z-phase signal is output to the first parallel / serial conversion circuit 32. The abnormality detection sensor 31 detects an abnormality in the motor body 4, for example, an abnormality in temperature, and outputs a sensor signal to the first parallel / serial conversion circuit 32.

The first parallel-serial conversion circuit 32 inputs the Pu phase signal, the Pv phase signal, the Pw phase signal, the Z phase signal, and the sensor signal as shown in FIGS. 1 and 2, and parallelizes these signals. -Serial conversion, and outputs the serial signal to the second parallel / serial conversion circuit 33. The second parallel-serial conversion circuit 33 performs parallel-serial conversion of this serial signal input and each of the A-phase and B-phase signals, and transfers the serial signal from the line driver 35 of the transmission circuit section 34 to the transmission path 3. Send out. In FIG. 2, the clock divider circuit 36
Divides the transmission clock and supplies it to the first parallel-serial conversion circuit 32.

The transmission line 3 includes two signal lines 37 and 38 for transmitting a serial signal from the servo motor 1 to the servo driver 2 and a signal line 39 for giving a voltage of +5 V and 0 V from the servo driver 2 to the servo motor 1. 4 in total consisting of 40
The signal lines are included, and the number of signal lines is significantly reduced as compared with the 17 lines of the device example shown in FIG.

Next, the servo driver 2 includes the receiving circuit unit 41 and the first and second circuits.
Each circuit such as serial / parallel conversion circuits 42, 43 is built in. The receiving circuit unit 41 has one line receiver 44 for receiving a serial signal, and the received signal is received from the line receiver 44 by a first serial / parallel conversion circuit.
Given to 42. The first serial-parallel conversion circuit 42 performs serial-parallel conversion on a serial signal,
Separated into A phase detection signal, B phase detection signal and other detection signals,
The other detection signals are further given to the second serial / parallel conversion circuit 43, serial-parallel converted, and
A phase detection signal, a Pv phase detection signal, a Pw phase detection signal, a Z phase detection signal, and an abnormality detection signal are generated. In FIG. 2, the clock divider circuit 45 divides the received clock and gives it to the second serial-parallel converter circuit 43, or the line abnormality detection circuit 46 detects an abnormality in the transmission line 3 such as disconnection of the signal line. Detects and raises an alarm.

FIG. 3 shows another embodiment of the present invention, and FIG. 4 shows its time chart.

In this embodiment, the logical product of the Pu phase signal, the Pv phase signal and the Pw phase signal is always zero (Pu · Pv · Pw = 0), and the logical sum is always 1 (Pu + Pv + Pw = 1). It is configured by focusing on the fact that the result does not change even if the Z-phase signal is added to the logical product or the logical sum, and when the sensor signal is turned on, the state opposite to the above logic is forced. By reducing the transmission signal by 2 bits. In this case, if the servo motor 1 has an abnormality such as a temperature, the condition for stopping the driving is that the Pu phase signal, P
Even if the v-phase signal, the Pw-phase signal and the Z-phase signal are not obtained, there is no practical problem.

In FIG. 3, the servomotor 1 incorporates a logic circuit 47 including one AND circuit 51 and three OR circuits 48 to 50, and a Z-phase signal (see FIG. )), Pu phase signal (Fig. 4 (4)), Pv phase signal (Fig. 4 (5)), Pw phase signal (Fig. 4 (6)), and sensor signal (Fig. 4 (7)) Is entered. The Z-phase signal is set to be generated when the Pu-phase signal is logic "1" and the Pu-phase signal and Pw-phase signal are logic "0", and the X-phase signal is inverted to the Pu-phase signal. AND (Pu ・) is an AND circuit
It is generated by 51 (Fig. 4 (8)). This AND circuit
The logical sum (Pu. + Sensor signal) of the output of 51 and the sensor signal is obtained by the OR circuit 50, the logical sum of the Pv phase signal and the sensor signal (Pv + sensor signal) is obtained by the OR circuit 49, and the Pw phase signal is obtained. Logical sum with sensor signal (Pw + sensor signal)
Are generated by the OR circuit 48, and the respective OR outputs ((9) to (11) in FIG. 4) are given to the first parallel-serial conversion circuit 32 and converted into serial signals. Further, the serial signal and each of the A-phase and B-phase signals are given to the second parallel / serial conversion circuit 33 to be parallel-serial converted, and the serial signal is transmitted.
It is sent from the line driver 35 of 34 to the servo driver 2 via the transmission line 3.

In the servo driver 2, the transmission signal is received by the line receiver 44, and the received signal is converted by the first serial / parallel conversion circuit 42 into each detection signal of A phase and B phase and other detection signals. After converting the other detection signals into parallel signals by the second serial-parallel conversion circuit 43,
It is given to the logic circuit 52.

The logic circuit 52 includes a NOR circuit 53, an OR circuit 54, and an AND circuit 55. The NOR circuit 53 includes the demodulated logical sum signals (Pu. + Sensor signal), (Pv + sensor signal), (Pw +). The sensor signal) is given and the Z-phase detection signal ((12) in FIG. 4) is obtained. Further, the output of the NOR circuit 53 and the logical sum signal (Pu + sensor signal) are given to the OR circuit 54 to obtain the Pu phase detection signal, and the logical sum signal (Pv + sensor signal) and the logical sum signal (Pw + Sensor signal)
And become the Pv phase detection signal and the Pw phase detection signal as they are.
Furthermore, the AND circuit 55 is given the logical sum signals (Pu. + Sensor signal), (Pv + sensor signal), and (Pw + sensor signal), and the AND circuit 55 is in the state where the logical product of the three is "1". It is detected to generate an abnormality detection signal ((13) in FIG. 4).

Then, when the servomotor 1 is operated, the signals of the A phase and B phase of the rotary encoder 6 are sent to the second parallel-serial conversion circuit 33, and the Z phase signal of the rotary encoder 6 and the pole sensor 5 are sent. The Pu phase signal, the Pv phase signal, the Pw phase signal, and the sensor signal of the abnormality detection sensor 31 are sent to the first parallel / serial conversion circuit 32.
First, in the first parallel / serial conversion circuit 32, the Z-phase signal, the Pu-phase, Pv-phase, Pw-phase signals, and the sensor signal are converted into serial signals, and then the serial signals and the A-phase and B-phase signals are converted. Each signal is converted into a serial signal by the second parallel / serial conversion circuit 33, and then sent to the line driver 35 of the transmission circuit unit 34. This serial signal is sent to the servo driver 2 via the transmission line 3 and received by the line receiver 44 of the receiving circuit unit 41. After that, this received signal is the first and second
Are sequentially given to the serial / parallel conversion circuits 42 and 43 of
The first serial-parallel conversion circuit 42 generates the A-phase and B-phase detection signals, and the second serial-parallel conversion circuit 43 further generates the Pu-phase, Pv-phase, Pw-phase detection signals and the Z-phase. A detection signal and an abnormality detection signal are generated.

<Effects of the Invention> As described above, the present invention converts the Z-phase signal of the rotary encoder, the magnetic pole position detection signal of the pole sensor, and the sensor signal of the motor abnormality detection sensor into a serial signal, and then converts the serial signal and the rotary signal. Phase A of encoder, B
Since each phase signal is converted into a serial signal and transmitted via the transmission line, not only is a dedicated signal line for individually transmitting these signals unnecessary, but also for transmitting these signals. The number of signal lines can be greatly reduced by integrating the signal lines into one. Further, the transmission bit length of the signal can be greatly reduced, and high-speed transmission can be achieved.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram showing a configuration of a signal transmission device for a servomotor according to an embodiment of the present invention, FIG. 2 is an electric circuit diagram showing a main part of the embodiment shown in FIG. 1, and FIG. FIG. 4 is an electric circuit diagram showing an essential part of a second embodiment of the invention, FIG. 4 is a time chart in the embodiment of FIG. 3, FIG. 6 is a time chart in the conventional example of FIG. 1 ... Servo motor, 2 ... Servo driver 3 ... Transmission path, 4 ... Motor body 5 ... Pole sensor 6 ... Rotary encoder 32, 33 ... Parallel / serial conversion circuit 34 ... Transmission circuit section

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenji Sawai, Kenji Sawai, Tateishi Electric Co., Ltd., 10 No.10 Hanazono Todo-cho, Ukyo-ku, Kyoto City, Kyoto Prefecture (56) Reference JP-A-61-69386 (JP, A) JP-A-1 -50785 (JP, A) JP-A-63-148885 (JP, A)

Claims (1)

(57) [Claims] 1. A signal transmission device for a servo motor, comprising: a servo motor having a pole sensor, a rotary encoder, and a motor abnormality detection sensor, and a servo driver connected to the servo motor via a transmission path, wherein the servo motor is a pole sensor. A first conversion circuit unit for inputting and converting the magnetic pole position detection signal output by the motor controller, the Z-phase signal output by the rotary encoder, and the sensor signal output by the motor abnormality detection sensor into a serial signal; Second conversion circuit section for inputting and converting the serial signal output from the conversion circuit section and the A-phase signal and the B-phase signal output from the rotary encoder into a serial signal, and the second conversion circuit section outputs And a transmission circuit section for transmitting a serial signal to the transmission path.