JPH11216575A - Control device in welding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To use plural welding machines as general purpose welding machines when they are used as individual welding machines, and as welding machines for large current welding when they are parallely connected for use. SOLUTION: When master slaves SW 27 of plural control devices are all set on a master timer side, all of the control devices supply the current to welding guns 50 independently. When the master slaves SW 27 of all the control devices are set on the slave side except one control device, the control devices being set on the slave timer side are synchronizingly moved according to the command of the control device being set on the master timer side for supplying the large current to the welding guns 50 via transformers 40A, 40B...... being parallely connected. To synchronize each control device, the time of each internal clock 26 is matched by the reset signal so as to actuate each control device relative to this time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a plurality of welding machines each used as a general-purpose welding machine when used alone, and as a welding machine for large current welding when a plurality of welding machines are used. The present invention relates to a control device for a welding machine that can function.

[0002]

2. Description of the Related Art In recent years, inverter type resistance welding machines have been widely used. However, steel sheets (made of materials having different melting points) having a surface treatment such as plated steel sheets and aluminum sheets have been used. When welding a plate having a large thermal conductivity, a very large current is required to melt the plate.

[0003] In the case of such a welding, a single welding machine cannot provide a necessary welding current.
No. 81671 (see FIG. 9) or JP-A-9-854
As disclosed in Japanese Patent Publication No. 58 (see FIG. 10), a plurality of the same welding machines are connected in parallel to obtain a current necessary for welding.

[0004]

However, the following problems occur in the conventional apparatus in which a plurality of welding machines are connected in parallel to prepare for high-current welding as described above.

For example, as shown in FIG. 9, when a plurality of welding machines are simply connected in parallel, wiring for collecting a starting signal and an error signal in one place is required.
The wiring work becomes very complicated.

[0006] Further, as shown in FIG.
To sum up, even if only a plurality of current supply units are connected in parallel, wiring to the inverter for each current supply unit is necessary in the same way, and if noise occurs in this wiring,
Problems such as a possibility that a semiconductor element constituting the inverter may be destroyed by the influence of the noise occur.

Further, simply connecting the current supply units in parallel as shown in FIGS. 9 and 10 cannot completely match the start and stop timings of the current supply units. In some cases, it may not be possible to obtain a welded state. Further, if a plurality of welding machines are connected in parallel in this way, there is a problem that the welding machine cannot be used as a general-purpose machine.

The present invention has been made in view of such conventional problems, and when a plurality of welding machines are used as a single welding machine, the welding machine is used as a general-purpose welding machine. It is an object of the present invention to provide a control device for a welding machine that enables a plurality of welding machines to be used as a welding machine for high-current welding when connected and used.

[0009]

The present invention for achieving the above object is constituted as follows for each claim.

According to the first aspect of the present invention, an internal clock used for synchronizing with a control device of another welding machine when the control devices of a plurality of welding machines are connected in parallel, Communication means for performing mutual communication with a control device of another welding machine when the control device is connected in parallel, and setting means for setting specifications when the control devices of a plurality of welding machines are connected in parallel; A control unit that outputs an operation signal based on a command signal from an external device or the communication unit and the time of the internal clock, and a specification set by the setting unit; and a welding gun based on the operation signal from the control unit. And a current supply means for supplying a current to the welding machine.

According to a second aspect of the present invention, in the control device for a welding machine according to the first aspect, the setting means can set a master timer and a slave timer as specifications. The control means, when the setting means is set to a master timer, outputs an operation signal based only on a command signal from an external device or the communication means, and is connected in parallel with the internal clock. A reset signal is output to the control devices of all the welding machines via the communication unit. On the other hand, when the setting unit is set to the slave timer, the reset signal input via the communication unit is output. And resetting the internal clock based on the command, and outputting an operation signal based on a command signal from the communication unit.

According to a third aspect of the present invention, in the control apparatus for a welding machine according to the first or second aspect, the control means further includes a terminal device for outputting a command signal, and The means outputs an operation signal based on a command signal from the terminal device.

According to a fourth aspect of the present invention, in the control apparatus for a welding machine according to the third aspect, the control means includes a command signal from the terminal device when the setting means is set to a slave timer. Is input.

[0014]

The control apparatus for a welding machine according to the present invention, constructed as described above, has the following effects.

According to the first aspect of the present invention, when the control devices of a plurality of welding machines are connected in parallel, an internal clock used for synchronizing with the control devices of other welding machines is provided. A communication means for performing mutual communication with a control device of another welding machine when a control device of a welding machine is connected in parallel, and a setting for setting specifications when the control devices of a plurality of welding machines are connected in parallel. Means, a control signal for outputting an operation signal based on a command signal from the external device or the communication means and the time of the internal clock, and a specification set by the setting means, so that a plurality of welding machines The control devices can be operated simultaneously in a synchronized state, and a desired welding state can be obtained.

According to the second aspect of the present invention, when the setting means is set to the master timer, the control means outputs an operation signal based only on a command signal from an external device or a communication means. And outputs a reset signal to the internal clock and all the welding machines connected in parallel via the communication means. On the other hand, when the setting means is set to the slave timer, the communication means The internal clock is reset on the basis of a reset signal input through the CPU and an operation signal is output based on a command signal from the communication means. The control device of the welding machine can operate independently or in synchronization with the control device of another welding machine to obtain a desired welding state. Door will be able to. In addition, by setting the slave timer, it operates in synchronization with the control device of the welding machine set as the master timer.

Therefore, the individual control device can be used as a general-purpose welding machine only by setting the individual control device to a master timer or a slave timer.
A plurality of control devices can be started at the same time and used as a welding machine for high-current welding.

According to the third or fourth aspect of the present invention, the control means further includes a terminal device for outputting a command signal, and the control means sets the setting means to a slave timer. In this case, the command signal from the terminal device is input, so that the control devices of the plurality of welding machines need only be connected to the common communication line of the respective control devices. No complicated wiring work is required.

[0019]

Next, an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a schematic configuration of a control device for a welding machine according to the present invention.

A master timer 20 shown in FIG. 1 is a control device which is a main control unit of an operation command of a control device of another welding machine connected via a communication line. Setting on the timer side allows the set control device to function as a master timer. Also, a slave timer 1 shown in FIG.
Reference numeral 20 denotes a control device that operates in synchronization with the master timer based on a command from the master timer 20. By setting a slave timer SW27 to be described later on the slave timer side, the set control device is activated. It functions as a slave timer.

That is, the control device set to the master timer is the main control device when a large number of welders are connected in parallel to perform high-current welding, and the control device set to the slave timer is the main control device. The sub-control device operates in synchronization with the sub-controller.

Therefore, when the master-slave SWs of a plurality of control devices connected via a communication line are all set on the master timer side, all the control devices function as master timers, and each control device operates as a master timer. The current to the welding gun 50 is controlled independently of each other. That is, each of the control devices can be used as an independent control device.

On the other hand, when the master-slave SW of the other control devices except the one control device is set to the slave side, the control device set as the slave timer is set as the master timer. Moves all at once according to the command of the control device, and enables high current welding. That is, the control device that functions as a master timer and the control device that functions as a slave timer can be used as one control device that performs high-current welding.

As shown in FIG. 1, a master timer 20 has a rectifier 21 for rectifying an alternating current from the commercial power supply 10.
Is provided, and the rectified current is output to the inverter unit 22. In the inverter unit 22, an AC current having a desired frequency is generated, and the AC current is transformed by a transformer 40 </ b> A to produce a welding gun 50.
To supply.

The commercial power supply 10, the rectifier 21, the inverter 22, and the transformer 40A constitute a current supply means for supplying a current to the welding gun 50 based on an operation signal from the control unit 23.

A terminal device 30, such as a setting / monitor terminal or a PB (pendant), performs mutual communication with a control device of another welding machine when the control devices of a plurality of welding machines are connected in parallel. , Setting of welding conditions and the like, and monitoring of the welding state and the like. These communications are performed via a communication line. The P / B communication processing unit 24 that functions as a control unit performs communication with the terminal device 30 and communication between the control unit 23 and the drive circuit 25.

The control section 23 functions as control means, and receives a start signal from an external device (not shown),
An error signal is output to an external device, a start signal (command signal) transmitted from the terminal device 30 via a communication line, and setting information such as welding conditions are input via the P / B communication processing unit 24. A reset signal of an internal clock 26 described later is input and output, and further, specification information relating to the setting of a master timer or a slave timer is input from a master slave SW 27 described later.

The internal clock 26 is used for synchronizing with a control device of another welding machine when the control devices of a plurality of welding machines are connected in parallel. It is reset when the device receives a reset signal from a control device set as a master timer.

The master-slave SW 27 functions as setting means for setting specifications when a plurality of control devices for the welding machines are connected in parallel. By switching this switch, the specifications of the master timer and the slave timer are changed. Can be set.

The control unit 23 is an external device or the terminal device 3
An operation signal is output to the drive circuit 25 based on the command signal from 0, the time of the internal clock 26, and the specifications (master timer, slave timer) set by the master-slave SW 27. The drive circuit 25 operates the inverter section 22 based on the operation signal.

When set to the master timer, the control unit 23 outputs an operation signal to the drive circuit 25 based on only a start signal (command signal) from an external device or the terminal device 30, and Output a reset signal to the internal clock 26 and the control device of all the welding machines connected in parallel via the P / B communication processing unit 24,
On the other hand, when the master / slave SW 27 is set as a slave timer, the internal clock 26 is reset based on the reset signal input via the P / B communication processing unit 24 and the P / B communication processing unit 24 And outputs an operation signal based on the command signal. The drive circuit 25 operates the inverter section 22 based on the operation signal.

The control device set as the slave timer 120 has exactly the same configuration as the above control device.

FIGS. 2 and 3 are flowcharts showing the operation of the control device set as a master timer and the control device set as a slave timer. This flowchart will be described with reference to the timing charts of FIGS. Since the control device in which the master-slave SW 27 is set on the master timer side functions as a master timer, the processing in the flowchart shown in FIG. 2 is performed, and the control device in which the master-slave SW 27 is set on the slave timer side is performed. Functions as a slave timer, the processing of the flowchart shown in FIG. 3 is performed.

First, when the power of these control devices is turned on, the internal clock 26 of each control device is initialized (initial processing). As shown in the figure, first, the internal clock of the master timer is initialized, and when the initialization is completed (OK), the slave timers are sequentially initialized. The communication for the initial processing is performed via the P / B communication processing unit 24.

Next, the terminal device 30 outputs a reset signal, and the internal clocks 26 of all the control devices (master timer and slave timer) are reset to 0 based on the reset signal. This reset processing is performed by broadcast communication. After the reset, each internal clock starts counting time independently.

When the start signal is output from the external device or the terminal device 30, the start signal is input to the control unit 23 of the control device of the master timer via the P / B communication processing unit 24. As shown in the flowchart, the welding pattern and the execution start time inputted together with this start signal as a command signal from an external device are broadcast to all the slave timer control devices as shown in the timing chart of FIG. Communication is performed (S1). On the other hand, the control unit 23 of the control device of the slave timer compares the welding pattern sent via the communication line and the execution start time with the P / B.
Input through the communication processing unit 24, and when the input is completed,
The K signal is output (setting communication communication processing). The timing chart of this process is as shown in FIG. 7, but a command to write the setting is issued from the terminal device 30 (S11).

All the control devices wait until the designated time comes, and when the designated time comes, they start welding at the same time (S2, S3, S12, S13).

The monitoring of the welding result (in what state (for example, the current value) the welding is performed) can be performed for all the control devices according to the command of the terminal device 30 as shown in the timing chart of FIG. it can. In the figure, the slave 1 timer requests monitor data.

As described above, since a plurality of control devices connected in parallel start welding all at once from the exact same time in a completely synchronized state, welding defects due to timing deviation do not occur as in the related art. .

In the control apparatus for a welding machine according to the present invention, by setting a master timer, each of the control apparatuses can supply a current to a separate welding gun independently of the other control apparatuses. (It is necessary to connect a welding gun to the transformer of each control device), set the slave timer, and connect the transformer of the slave timer to the welding gun of the master timer. A current can be supplied to the welding gun. The setting of the master timer or the slave timer can be easily performed, and since the slave timer and the master timer are connected to each other via a communication line, signals are collected in one place as in the conventional case. Such wiring work and wiring for connecting the inverters are not required. In addition, even when the number of control devices is increased, it is only necessary to connect the control devices to a communication line, and addition and change operations are facilitated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a control device for a welding machine according to the present invention.

FIG. 2 is a flowchart illustrating an operation of a control device set as a master timer.

FIG. 3 is a flowchart showing an operation of a control device set as a slave timer.

FIG. 4 is a timing chart showing initial processing communication.

FIG. 5 is a timing chart showing processing for resetting an internal clock.

FIG. 6 is a timing chart showing a synchronization process between a welding pattern and its execution start time.

FIG. 7 is a timing chart showing setting communication.

FIG. 8 is a timing chart showing monitor read communication.

FIG. 9 is a block diagram showing a schematic configuration of a conventional welding machine for large current welding.

FIG. 10 is a block diagram showing a schematic configuration of a conventional welding machine for large current welding.

[Explanation of symbols]

 20 Master timer 23 Control part 24 P / B communication processing part 26 Internal clock 27 Master-slave SW

Claims (4)

[Claims] An internal clock (26) used to synchronize with a control device of another welding machine when the control devices of a plurality of welding machines are connected in parallel, and a control device of the plurality of welding machines is connected in parallel. Communication means (24) for performing mutual communication with a control device of another welding machine when connected
And setting means (27) for setting specifications when the control devices of a plurality of welding machines are connected in parallel; and a command signal from an external device or the communication means (24) and the time of the internal clock (26). A control means (23) for outputting an operation signal based on the specification set by the setting means (27); anda current supply means (10, 10) for supplying a current to the welding gun based on the operation signal from the control means. 21, 22, 25, 40). A control device for a welding machine, comprising: 2. The setting means (27) is capable of setting a master timer and a slave timer as specifications, and the control means (23, 24) sets the master timer to a master timer. If set, it outputs an operation signal based only on a command signal from an external device or the communication means (24) and controls the internal clock (26) and all the welding machines connected in parallel. A reset signal is output to the device via the communication means. On the other hand, when the setting means is set to a slave timer, the internal clock is output based on the reset signal input via the communication means. 2. The control device for a welding machine according to claim 1, wherein the control signal is reset and an operation signal is output based on a command signal from the communication unit. 3. The control means (23) is further provided with a terminal device (30) for outputting a command signal, and the control means (23) is provided on the basis of a command signal from the terminal device (30). The control device for a welding machine according to claim 1, wherein the control device outputs an operation signal. 4. The control means (23), wherein the setting means (27)
The terminal device when is set to the slave timer
The control device for a welding machine according to claim 3, wherein a command signal from (30) is input.