JPS6154742A - Coupling circuit of control system - Google Patents

Abstract

PURPOSE:To obtain the coupling circuit of a control system which uses a high- speed type photocoupler and has tolerance to a noise and high reliability by equipping an input system with a photocoupler for input connected to the output terminal of a DC stabilized power source through a switching element which is switched in synchronism with the half-wave rectification output of a rectifying means. CONSTITUTION:The output of a diode bridge DB connected to a signal line 7 is connected to the input terminal of the DC stabilized power source 14 which is stepped down and stabilized at the driving source voltage of the high-speed type photocoupler. Then, a transmit signal Vs sent through the signal line 7 is rectified by the diode D0 on half-waveform basis and its half-waveform rectification output is applied to the base of a transistor (TR)Q, which is switched in synchronism with a waveform applied to its base to drive the photocoupler PH. Therefore, the photocoupler PH outputs the unipolar wavefom of the transmit signal V as it is and the signal is sent to a signal processing logical part 9 as it is without requiring any frequency dividing circuit.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field 1 The present invention relates to a control system coupling circuit connected to a time division multiplex transmission system. [Background technology] Figure 3 shows the control system configuration of a multiplex transmission system and a distributed processing system. This shows a system connection diagram in which the control system device 1 is connected to the CPυ unit A as shown in the fjS4 diagram.
is composed of a CPU 2 and an inter 7/8 6, and temperature control a is provided via an internal bus 4a for input and an internal bus 4b for output.
-The system is designed to take in various monitoring data and control the sequencer, etc. based on the monitoring data, and the system itself is designed to be able to perform independent control and monitoring. For the II supervisory device 2, there is a terminal block 3 consisting of the circuit shown in the above-mentioned ms diagram, and a human output interface 7 consisting of an interface 5 for inputting and outputting control data and monitoring data to the CPU 2 side. The Ace Unisoto 13 and the IJ gland 7 are connected to each other, and the terminal blocks 3 are sequentially called up from the middle 9! and all control and monitoring devices 12 to control the i11 system Vcli.
It is designed to exchange data with 21. Figure 6 (
a) (1+) is the transmission signal V9 which is transmitted cyclically and sequentially from the central control and monitoring device 2 and the terminal block 11.
・This indicates the return signal VB sent back from the start signal ST, 7dress data signal AD, and control data signal S.
D. Return standby (composed of U WP. The terminal block 3 receives the transmission signal Vs transmitted from the central control and monitoring device i2 via the ff [7] via the coupling circuit 8).
Then, under the control of the signal path theory J1rIS9, the address determination unit 10 determines whether or not the calling address sent by the address data signal AD matches the self-set address. The il control signal discriminator 11 takes in the address data (control data signal SD sent following No. II AD, outputs control data for each bit, and when the control data is complete, it becomes 7.
It outputs the address matching signal, transfers the control data to the CP II unit 8 via the interface 5, and also stores the monitoring data into the monitoring manual output section 12 via the interface 5, synchronizing it with the return standby signal WP. and send it back. Note that the return fff signal V11 for returning monitoring data is a so-called current mode signal that performs data transmission by short-circuiting a pair of signal lines via an appropriate impedance depending on the data. By the way, the above-mentioned 1il111 system device 1 has its own '@ source, and the above-mentioned transmission (ff signal vs. Since it consists of a pulse voltage signal of ±24V at the pole, it is necessary to JELN both systems.Therefore, as shown in FIG. Figure 8 (b
), full-wave rectification is performed, the photocoupler PH is turned on by switching the transistor Q at the output point of the full-wave rectification waveform, and a detection pulse synchronized with the zero-crossing point is obtained from the photocoupler PH, and its detection □ The original unipolar pulse waveform was restored using a frequency dividing circuit 13 such as a D-type 7 lipprop. However, in the conventional circuit, the light-emitting diode LED of the photocoupler PH is connected through the diode D, resistor R+, transistor Q, and resistor R2, so the applied voltage from photocube to PH is close to 21) V, and at present it is a high-speed type. Fig. 8 (e) cannot be used.
), the detected pulses tended to become dull, as shown by the broken line. This means that a voltage of nearly 20V is applied to the phototransistor PT, and the light emitting diode LED' is driven by the transistor Q1 of the monitoring human power output section 12! A similar problem will occur on the photocoupler PH' side for the return No. 48 that will be sent back to IIIJ. In addition, the pole (in order to obtain a short-time width detection pulse
A resistor R connected to the base of the NP type transistor Q
The value of 1 must be increased, which causes the problem of unstable operation, and there is also the risk of malfunction due to noise since the frequency divider circuit 13 is triggered by the detection pulse to restore the data signal. Ta. [Object of the Invention] The present invention has been made in view of the above-mentioned points, and its purpose is to provide a coupling circuit for a highly reliable control system that can use a high-speed photocoupler and is resistant to noise. There is something to do. [Disclosure of the invention]. FIG. 1 shows a circuit according to an embodiment of the present invention, in which the output of the diode DB connected to the R line 7 is a DC stabilized power supply that drops and stabilizes the drive power supply voltage (for example, 5V) of a high-speed type photocoupler. 14, and the output terminal of the DC stabilized type [14 is connected to a light emitting diode LED of an input photocoupler PH via a resistor R1 and a transistor Q.
is half-wave rectified with diode D0 at the base and resistors R1, R
6 and R1 to connect a certain voltage. In addition, at the output end of the DC stabilized power supply 14, there is a photocoupler for return.
A series circuit is connected between a phototransistor []' of IBI and a resistor 1 (,).The voltage generated across the resistor is connected to the output terminal of the diode bridge DB, and the resistor The transmission signal s shown in Fig. 2(a) sent via the signal m7 is subjected to half-wave rectification tIL by the diode D0, and the transmission signal s shown in Fig. 2(b) is transmitted via the signal m7. The half-wave rectified output is applied to the base of the transistor Q, and the transistor Q switches in synchronization with the waveform applied to the base of the photocube.
Drive H. Therefore, e) the unipolar waveform of the transmission signal vg is generated as it is at the output of the coupler PH, and can be sent as is to the signal processing logic unit 9 without the need for a frequency dividing line. On the other hand, when the transistor Q is driven by the output of the monitoring human power sending unit 12, the photocoupler PH' is also driven in synchronization with it, and the output turns on and off the transistor Q2. Therefore, transistor Q! When the signal line 7 is turned on, the signal line 7 is short-circuited and a current mode return signal is sent out. [Results of the invention 1] The present invention includes a rectifying means that is provided in the terminal block and half-wave rectifies the transmission number 48 sent through the signal line, and a rectifying means that rectifies the transmission signal and stabilizes the voltage to drive the photocoupler. The human-powered system is equipped with a DC stabilized power source that outputs a DC stabilized power source, and an input converter connected to the output end of the DC stabilized power source via a switching element that is switched in synchronization with the half-wave rectified output of the rectifying means. It is able to directly restore the transmitted signal, and compared to the conventional method of detecting zero-crossing points, it has the effect of improving reliability against noise and eliminating the need for companion circuits. Moreover, since DC stabilization mW is used, it is possible to obtain the voltage of an 11゜ quadruple type photocoupler, and there is an effect that the generation of waveform distortion can be eliminated during waveform restoration.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, ft52 is a waveform diagram for explaining the operation of the same as above, Fig. 3 is an overall configuration diagram of the basic system of the present invention, and Fig. 4 is a control system device of the same as above. Figure 5 is a circuit diagram of the terminal block used in the above, Figure 6 is an explanatory diagram showing a 7-ohm transmission signal used in the same, rjs7 is a circuit diagram of a conventional example, and Figure 8 is the same as the above. 1 is a waveform diagram for explaining the operation of
H line, 8 is a coupling circuit, 14 is a DC stabilized power supply, D is a diode, Q is a transistor, and PH is a photocoupler. Agent Patent Attorney Ishi 1) Ai 7 Figure 2 Figure 3

Claims (1)

[Claims] (1) Connect the central control and monitoring device of the multiplex transmission system to the terminal block of each control system device of the distributed system system with a unique address set using a pair of signal lines, and call the terminal block from the central control device. A bipolar transmission signal consisting of an address data signal, a control data signal, and a return standby signal is sequentially and cyclically sent to each terminal block, and the address data of the transmission signal received via the signal line at the terminal block is In a control system that captures the control data of the transmission signal when it matches its own unique address data and returns the data from the control system device in synchronization with the return standby signal of the transmission signal, the control system is provided in the terminal block. , a rectifying means for half-wave rectifying the transmission signal sent through the signal line, a DC stabilized power supply for rectifying the transmission signal and stabilizing it down to a voltage for driving the photocoupler, and the above-mentioned at the output end of the DC stabilized power supply. A coupling circuit for a control system, characterized in that the input system includes an input photocoupler connected via a switching element that is switched in synchronization with the half-wave rectified output of a rectifier.