JPH07108385A - Communication network system for resistance welding machine - Google Patents

Abstract

PURPOSE:To carry out centralized control of plural welding timers by utilizing a computer. CONSTITUTION:A centralized control system of welding lines consisting of plural welding machine groups set up in a series of welding lines, a welding timer group which controls various mechanical and electrical operations of these welding machine groups separately, one centralized controlled which combines this welding timer group by a communication network line to carry out package control and one host computer combined with this centralized controller is formed. The centralized controller is then provided with an input and output circuit to exchange synchronizing signals with various devices except the welding machines incorporated into the welding lines, a control circuit to carry out control of input and output of these and starting control of the welding timer group, a storage device to store those programs and a program input means. In order to control welding operation of an individual welding timer by the centralized controller, input and output circuits of each welding timer with a relay circuit, a PC, a robot, etc., and connections of those are omitted and reliability is enhanced by the minimum number of parts.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a system for centrally managing a plurality of resistance welding machine control devices (hereinafter referred to as welding timers) using one computer.

[0002]

2. Description of the Related Art FIG. 3 is an electrical block diagram showing an example of the configuration of a conventional communication network system, in which each welding timer has an input / output, and a synchronizing signal is directly exchanged with a peripheral device.
The conventional communication network system has one host computer installed in the information control room on the automated welding line.
The host computer and the welding timers corresponding to many welding machines installed at the welding site are connected to each other by a communication network line through a centralized control device having a built-in communication circuit and network drive circuit to communicate with each other. Centralized to read and write welding conditions from the host computer to individual welding timers, and to monitor welding information such as welding current detected by the welding timers via sensors to monitor welding quality and maintenance. It was a management system.

In this case, the central control device installed between the host computer and the welding timer group is used to amplify a weak communication signal from the computer so as to withstand long-distance transmission in the factory, and to use a large number of welding timers. It also had the function of consolidating the generation of random data transmission requests to the host computer and converting it into a series of data formats that can be processed by one host computer.

The welding operation of each welding timer is activated or interlocked by an input / output signal from a relay circuit, a PC, that is, a programmable controller, a robot, or the like, and is controlled independently of the communication network function. It had been. That is, the function of the communication network did not control the welding operation of each welding timer, and the function was limited to the welding condition program and its management, the welding result monitoring and its statistical processing.

Originally, ideally, if the centralized control device controls the welding operation of each welding timer via the communication network line, the input / output circuits of the relay circuit, the PC, the robot, etc. It is expected that the connection between the two can be omitted, and the cost and reliability can be improved by reducing the number of parts of the device components. On the other hand, on the other hand, control of the welding operation requires real-time synchronism with other equipment such as robots, jigs, and conveyors installed in the welding line.

[0006]

However, in the conventional communication network system as described above, the central control unit is only connected to the communication network line to the host computer and the welding timer, and the robot, jig, No means has been provided for synchronizing with other devices such as a carrier device. Even if the synchronization signals of these devices are input to the host computer, a delay occurs due to the processing time in the computer, and especially when the number of welding timer groups to be managed is large, the welding timer group and the robot or It was difficult to synchronize with other equipment such as jigs and conveyors.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a robot, a jig, and a transfer device incorporated on a welding line in a centralized control device of a communication network system. An input / output circuit for exchanging synchronization signals with other peripheral devices, a control circuit for controlling these inputs / outputs and starting control of a welding timer group, a storage device for storing those programs, and a program input means. In addition to controlling the welding operation of the welding timer in real time via the communication network line, it is also possible to read and write the welding conditions of individual welding timers, which are conventional functions, and monitor the welding current detected by the welding timer. We also made it possible to read data and manage welding quality and maintenance.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of a communication network system of the present invention. The centralized control device is a timer start control circuit that controls the start of many welding timers, a ladder logic control circuit that controls a PC, that is, a programmable controller, a robot, a transfer device, and other peripheral devices via input / output circuits. It consists of a welding start-up table, a storage device that stores ladder programs, and a communication circuit that communicates with the host computer. The host computer reads and writes the welding start table and the contents of the ladder program through this communication circuit, further reads and writes the data of each timer through the network drive circuit, and exchanges signals with the ladder logic control circuit and the timer start control circuit. It is possible to

The ladder logic control circuit is constantly operating in circulation according to the ladder program stored in the storage device. The operation is almost the same as that of a general PC, that is, a programmable controller. The ladder logic control circuit receives a synchronization signal from the peripheral device, that is, a work set completion signal, and sends a start signal to the timer start control circuit.

The timer start control circuit receives the start signal, reads the welding condition of each welding timer from the welding start table, and transmits the start signal for each welding timer via the network drive circuit and the network line. Each welding timer individually receives the start signal and drives the welding machine to perform welding. The welding data such as the welding current actually applied is monitored by the welding timer through the sensor attached to the welding machine, and the ladder logic is passed through the network line, the network drive circuit and the communication circuit in the central control unit. It is sent to the control circuit and the host computer.

The ladder logic control circuit inspects the abnormal data and, if necessary, takes an emergency measure to the peripheral device via the input / output circuit. The operation contents can be freely programmed in the ladder program. The host computer displays, prints out the detected data,
Alternatively, the information is accumulated internally and the welding quality, maintenance, etc. are centrally controlled, and the statistical processing is performed.

It should be noted that the cycle time of the welding line is fast, the ladder logic control circuit receives the synchronization signal from the peripheral device, and then the timer start control circuit transmits the start signal for each welding timer. May not be. In that case, the transmission of the welding condition contents to the welding timer and the transmission of the start signal are divided, the welding condition is transmitted to each welding timer in advance, and the timer start control circuit is received when the synchronization signal from the peripheral device is received. The ladder program may be programmed so that all send a start signal to all timers at the same time.

Next, FIG. 2 shows the contents of the welding start table and the operation of the timer start control circuit of the communication network system of the present invention. The peripheral device inputs a synchronization signal as a start command to the centralized control device, and the centralized control device sends the start number as the welding condition to each welding timer according to the welding start table programmed in the storage device via the network. . For example, when the start command 1 is input from the peripheral device, condition 2 is transmitted to the welding timer 1, condition 3 is transmitted to the welding timer 2, condition 6 is transmitted to the welding timer 3. Next, when the start command 2 comes, they are 6, 7, and 6 respectively.
And so on. Of course, start commands may be input randomly, not necessarily in numerical order.

[0014]

As described above, according to the present invention, a robot, a jig, a transfer device, etc. incorporated on a welding line can be provided through an input / output circuit built in a centralized control device of a communication network system. The control of the welding operation of the welding timer is performed in real time via the communication network line by the program that exchanges the synchronization signal with the equipment of the Since the centralized control device operates via the network line, it is possible to omit the input / output circuits of relay circuits, PCs, robots, etc. and individual welding timers, and the connections between them, and the cost can be reduced by reducing the number of parts of the device components. Down, improved reliability can be obtained. Also,
Coordination operation between units connected to the communication network can be facilitated.

[Brief description of drawings]

FIG. 1 is an electrical block diagram showing a configuration example of a communication network system according to the present invention.

FIG. 2 is an operation explanatory diagram of a welding trajectory table and a timer start control circuit of the system of the present invention.

FIG. 3 is an electrical block diagram showing a configuration of a conventional communication network system.

Claims (1)

[Claims] 1. A plurality of welding machine groups installed on a series of welding lines, a welding timer group for individually controlling mechanical and electrical operations of the welding machine group, and a welding network for the welding timer groups. In a centralized control system for a welding line consisting of one centralized control device that is connected by a line and collectively controlled, and one host computer that is connected to this centralized control device, welding that is incorporated on the welding line in the centralized control device And an input / output circuit for exchanging synchronization signals with various devices other than the welding machine, a control circuit for controlling these input / output and starting control of the welding timer group, a storage device for storing those programs, and a program input means. A communication network system for a resistance welding machine, characterized in that