JPH04252599A - Data transmission system - Google Patents

Abstract

PURPOSE:To build up the data transmission system inexpensively by employing a signal line, a clock line and a strobe line only for wiring so as to simplify the constitution of a communication equipment 20. CONSTITUTION:A control panel A is provided with a controller 1 and a communication equipment 10 and an operating panel B is provided with a communication equipment 20. The communication equipment 10 sends an output data bit by bit synchronously with a clock signal through a signal line L1. Simultaneously, the clock signal is sent from a clock line L3 to the communication equipment 20. The output data is stored in a shift register 22 of the communication equipment 20 synchronously with the clock signal. The communication equipment 10 stops the transmission of the clock signal at the end of transmission and sends a strobe signal. The communication equipment 20 reads the output data synchronously with the trailing of the strobe signal and reads the input data to a shift register 25 synchronously with the leading of the strobe signal and sends the input data to the communication equipment 10 through a signal line L2 synchronously with the clock signal.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention is implemented between a control panel equipped with a control device that controls the operation of equipment according to a program, and an operation panel provided on the equipment side that receives control from the control device. This relates to data transmission methods.

0002

[Background Art] Control of industrial equipment, etc. that construct manufacturing equipment is performed by a control device such as a programmable controller that sequentially controls the equipment according to a user program. Some machines are equipped with an operation panel for each work unit.

FIG. 3 shows a case where the control device 1 is directly connected to the operation panel B, and the operating status of the equipment is displayed using the light emitting diode LD provided on the operation panel B, and the operation is adjusted using the switch SW. It has been made possible to do so. However, when the control device 1 and the operation panel B are directly connected in this way, if the control panel equipped with the control device 1 and the operation panel B are separated, it becomes necessary to connect the control panel and the operation panel B. Since it is necessary to wire the same number of input/output wires, there is a problem in that it takes a lot of man-hours for wiring and for inspection after wiring.

Therefore, as shown in FIG. 4, a communication device 2 is provided on control panel A and operation panel B, and data is transmitted from control panel A side to operation panel B side and from operation panel B side to control panel A side. Two sets of signal lines L1 and L consisting of two pair lines for transmission
2 to connect the communication devices 2 and reduce the number of wires,
There is a method that reduces wiring man-hours and post-wiring inspection man-hours. Note that data transmission is performed in a differential manner using pair wires.

[0005]

[Problem to be Solved by the Invention] In this case, it is necessary to match the data timing and procedure in the communication devices 2, so it is necessary to configure each communication device 2 using a microprocessor (CPU). be. The communication device 2 in FIG. 4 includes a CPU 3, a ROM 4, a RAM 5, and a driver/receiver 6, and further requires an input/output buffer 7 in the communication device 2 on the operation panel B side. but,
With this configuration, the number of wires can be reduced, but there is a problem in that the communication device 2 requires a CPU, making it expensive.

The present invention has been made in view of the above-mentioned points, and its object is to provide a data communication system that can reduce the number of wiring lines and also make communication equipment inexpensive.

[0007]

[Means for Solving the Problems] In order to achieve the above object, in the present invention, a control panel equipped with a control device that controls the operation of equipment according to a program is provided with a first communication device, and a control panel equipped with a control device that controls the operation of equipment according to a program. An operation panel provided on a device side controlled by the device includes a second communication device, and a first signal line that transmits data from the first communication device to the second communication device;
A second signal line that transmits data from the second communication device to the first communication device, and a clock line and a strobe line that transmit the clock signal and strobe signal from the first communication device to the second communication device, respectively. Connect the above communication devices with
Transmits data one bit at a time from the first and second communication devices in response to a clock signal by a control unit including a CPU or the like provided in the first communication device, and instructs switching of the data transmission direction using a strobe signal. It is carried out.

[0008]

[Operation] The present invention achieves the second
The communication operation of the communication device is performed by the CPU included in the first communication device.
This is done under the control of a control unit consisting of a controller, etc., so that an expensive configuration such as the control unit described above is not required on the second communication device side, and furthermore, the wiring between each communication device is By requiring only one signal line, clock line, and strobe line, the number of wiring lines can be reduced.

[0009]

Embodiment FIG. 1 shows an embodiment of the present invention. In the case of this embodiment, the communication device 10 on the control panel A side is a 4-bit microcomputer (
11 (hereinafter referred to as a microcomputer), and a driver/receiver 12 that sends data from the microcomputer 11 to the operation panel B side and receives data from the operation panel B.

[0010] Here, the ROM1 built in the microcomputer 11
3 stores programs related to communication timing and procedures, and stores input/output data in the RAM 14. The communication device 20 equipped on the operation panel B is connected to the control panel A.
The driver/receiver 21 is equipped with a driver/receiver 21 that receives signals from the control panel A and sends signals to the control panel A, and is connected to the driver/receiver 12 on the communication device 10 side through signal lines L1, L2, clock line L3, strobe line L4, and ground. Line L
5 is connected. Signal lines L1, L3, L4
are connected to the output ports of the microcomputer 11, respectively, and the signal line L
1, data, a clock signal, and a strobe signal are sent from the communication device 10 to the communication device 20 via the clock line L3 and the strobe line L4, respectively. In addition, signal line L2
is connected to the input port of the microcomputer, and sends data from the communication device 20 to the communication device 10 via the signal line L2. A ground line L5 is provided to match the potentials between the communication devices 10 and 20. This communication device 20 includes a 32-bit shift register 22 that receives data from the communication device 10 in synchronization with a clock signal sent from the communication device 10, and a shift register 22 with a 32-bit configuration that receives data from the communication device 10 in synchronization with a clock signal sent from the communication device 10, and a shift register 22 that receives data from the communication device 10 in synchronization with a clock signal sent from the communication device 10, and a shift register 22 that receives data from the communication device 10 in synchronization with a clock signal sent from the communication device 10, and a shift register 22 with a 32-bit configuration that receives data from the communication device 10 in synchronization with a clock signal sent from the communication device 10. A buffer 23 with a latch function that reads and stores the data stored in the register 22, a buffer 24 with a latch function that stores input data such as the operating state of the switch SW provided on the operation panel B, and a buffer 24 with a latch function that reads and stores the data stored in the register 22, A shift register 25 having a 32-bit configuration is provided, which reads data to be stored in the buffer 24 in synchronization with the . Here, the data in the buffer 23 is output to each device, and the operating status of the device is displayed on the light emitting diode LD accordingly. Further, as the drivers for the respective drivers/receivers 12 and 21, open collector type drivers are used.

The communication method between the communication devices 10 and 20 of this embodiment will be explained below. The communication device 10 has a RAM1
By reading the output data stored in 4, the output data is transmitted bit by bit (FIG. 2(c)). This output data is sequentially stored in the shift register 22 on the communication device 20 side in synchronization with the clock signal CK shown in FIG. 2(a). Then, when the microcomputer 11 of the communication device 10 transmits 32 bits (8 words) of output data, it sends a strobe signal STB as shown in FIG. 2(b). In the communication device 20 that receives the strobe signal STB, the buffer 23 reads the output data stored in the shift register 22 all at once in synchronization with the rise of the strobe signal STB. In the communication device 20 receiving the strobe signal STB as described above, the shift register 25 reads the input data stored in the buffer 24 all at once in synchronization with the fall of the strobe signal STB. 2(a) sent from the communication device 10 after that.
The input data is sequentially sent bit by bit to the communication device 10 in synchronization with the clock signal CK shown in (FIG. 2(d)). When the communication device 10 receives 32 bits of input data sent from the communication device 20, it stores it in the RAM 14. In this way, in this embodiment, data can be transmitted using a simple communication method, so the communication device 10 can be configured with a 4-bit microcomputer, and there is no need to install a microcomputer or the like on the communication device 20 side. .

0012

Effects of the Invention As described above, the present invention has a control panel equipped with a control device that controls the operation of devices according to a program, and a first communication device that is connected to the device that receives control from the control device. The operation panel provided includes a second communication device, a first signal line for transmitting data from the first communication device to the second communication device, and a first signal line for transmitting data from the second communication device to the first communication device. The communication devices are connected by a second signal line for transmission, and a clock line and a strobe line for respectively transmitting a clock signal and a strobe signal from the first communication device side to the second communication device. CP installed in the device
Data is transmitted one bit at a time from the first and second communication devices in accordance with a clock signal from a control unit composed of a U, etc., and a strobe signal is used to issue a command to switch the data transmission direction. The communication operation of the communication device can be performed under the control of a control unit including a CPU included in the first communication device, and an expensive configuration such as the control unit described above is not required on the second communication device side. Can be configured inexpensively,
Furthermore, the wiring between each communication device requires only two signal lines, a clock line, and a strobe line, which has the advantage of reducing the number of wiring lines.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a communication device according to an embodiment of the present invention.

FIG. 2 is an explanatory diagram of the same operation as above.

FIG. 3 is an explanatory diagram showing a connection state between a conventional control device and an operation panel.

FIG. 4 is an explanatory diagram of a conventional communication system in which the number of signal lines is reduced.

[Explanation of symbols]

A Control panel B Operation panel L1, L2 signal line L3 Clock line L4 Strobe wire 1 Control device 10, 20 Communication device 11 Microcomputer A Control panel B Operation panel L1, L2 signal line L3 Clock line L4 Strobe wire 1 Control device 10, 20 Communication device 11 Microcomputer

Claims (1)

[Claims] Claim 1: A control panel equipped with a control device that controls the operation of the device according to a program is provided with a first communication device, and an operation panel provided on the device side that receives control from the control device is a second communication device. a first signal line that includes a communication device and transmits data from the first communication device to the second communication device;
A second signal line that transmits data from the second communication device to the first communication device, and a clock line and a strobe line that transmit the clock signal and strobe signal from the first communication device to the second communication device, respectively. Connect the above communication devices with
Transmits data one bit at a time from the first and second communication devices in response to a clock signal by a control unit including a CPU or the like provided in the first communication device, and instructs switching of the data transmission direction using a strobe signal. A data transmission method characterized by performing the following.