JPH02235583A - Welding system - Google Patents

Abstract

PURPOSE:To efficiently operate welding machines and to prevent the occurrence of defective welding by deciding the propriety of electrification based on the priority order of electrification and the number of machines electrifiable at the same time and limiting electrification on the plural welding machines to transmit and receive state signals mutually. CONSTITUTION:Commercial AC is fed from a main power source PS to the plural welding machines 12a1... and transmitted to welding gun 18a1... as a high-frequency current by welding current supply circuits 26a1... and converted into DC by welding transformers Tr1... and resistance welding is performed. At that time, the state signals of an electrified state, etc., are transmitted and received mutually via simultaneous electrification preventing devices 20a1... of respective welding control part. 16a1... Further, the propriety of electrification is decided according to these state signals and welding start commands from robot controllers 14a1... and electrification commands are transmitted to welding timers 24a1... of control circuits 22a1... In the simultaneous electrification preventing device 20a1 of the subject welding system, the propriety of electrification is decided based on the priority order of electrification and the number of machines electrifiable at the same time which are preset. By this method, the number of machines electrified at the same time is limited within the number of machines electrifiable at the same time and the occurrence of defective welding due to welding current shortage is prevented.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a welding system, and more particularly, among a plurality of welding machines constituting the welding system, welding machines are in a energized state, a de-energized state, and a energized standby state. Detects the number of welding machines, determines the order of energization of a given welding machine, and determines whether or not to energize based on a preset number of welding machines that can be energized at the same time.
By outputting a signal indicating the energized state, energized standby state, or de-energized state to other welding machines, it is possible to limit the number of simultaneously energized multiple welding machines to within the number of simultaneously energized machines, and each welding machine can be energized simultaneously. The present invention relates to a welding system that makes it possible to prevent welding defects caused by insufficient power supply to a machine.

[Background of the Invention] Conventionally, a plurality of welding machines are systemized in a welding processing line, and welding work is performed using these systemized plurality of welding machines, but all the welding machines in the system are operated at the same time. When welding, if the amount of electricity supplied to each welding machine is insufficient and this causes welding defects,
Or all welding machines may stop. Therefore,
In a welding system including a plurality of welding machines, it is desirable to perform energization control to limit the number of welding machines that are operated simultaneously according to the amount of power supplied.

Therefore, as a conventional technology of this kind,
As disclosed in No. 186980, a method has been developed in which the number of devices that can be simultaneously energized is set in advance according to the amount of power supplied, and energization is permitted only when the number of devices in the energized state is smaller than the set number.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 60-247482, there is a technology for prohibiting a certain welding machine from outputting a welding command signal to other welding machines when the welding machine is in operation. also exists.

Furthermore, as disclosed in Japanese Patent Application Laid-Open No. 61-20674, as an energization clock for three or more welding machines, the welding machines are ranked based on the input order of welding start command signals, and three or more welding machines are ranked based on the order of input of welding start command signals. There is also technology to control the energization of welding machines with a size larger than one.

However, in these conventional technologies, when the number of welding machines corresponding to the number of welding machines that constitute the welding system that can be energized is in the energized state, a new welding start command is issued to two or more welding machines that are in the de-energized state or in the energized state. If welding is performed on two or more welding machines at the same time, when one of the energized welding machines finishes welding and becomes de-energized, two or more of the welding machines are simultaneously de-energized or de-energized. At the same time, it becomes energized,
There is a possibility that Interotsuta may not operate properly.

In order to solve this problem, it is possible to use the ink lock function of the robot or sequencer to prevent simultaneous stoppage or simultaneous energization, but if this is implemented, the number of wiring points for the robot or sequencer will increase and the device Since the welding system itself becomes complicated and programming and teaching are required, new disadvantages arise, such as a decrease in the reliability of the welding system or an enormous amount of time required to construct the welding system.

[Object of the Invention] The present invention has been made in order to overcome the above-mentioned disadvantages, and when a command to start energization is input to a predetermined welding machine among a plurality of welding machines constituting a welding system, The number of welding machines that can be simultaneously energized is determined by determining the energization order and determining whether or not to energize based on the preset number of welding machines that can be energized simultaneously, including the predetermined welding machine, and the energization priority of the predetermined welding machine. This makes it possible to limit the current to the number of units that can be energized at the same time, thereby preventing problems such as voltage drop due to excessive current flowing beyond the rated power source of the welding system, and supplying power to each welding machine. It is an object of the present invention to provide a welding system that can prevent welding defects due to insufficient amount of electric power, and can also prevent simultaneous stoppage of welding machines.

[Means for Achieving the Object] In order to achieve the above object, the present invention comprises a plurality of welding machines, and the welding machines mutually transmit and receive status signals regarding energized state, de-energized state, and energized standby state. At the same time, the welding system performs welding by energizing a welding gun constituting the welding machine in accordance with the status signal and a welding start command from a welding start command means, wherein the welding machine at least simultaneously receives a welding start command. The welding machine has a simultaneous energization priority setting section, a simultaneous energization possible number setting section, and an energization propriety determination section when a welding machine is input with a welding start command exceeding the number of simultaneous energization machines. In this case, the energization priority is determined based on the priority determined in the simultaneous energization priority setting section, and the number of simultaneously energized devices is limited to within the number of devices that can be energized simultaneously set in the number of devices that can be energized simultaneously. It is characterized by controlling.

[Embodiments] Next, preferred embodiments of the welding system according to the present invention will be described in detail with reference to the accompanying drawings.

In FIG. 1, reference numeral 10 indicates a welding system according to this embodiment. The welding system 10 has N (N=1,
2,...-n) DC welding machines 12a1 to 12a,,
(hereinafter referred to as a welding machine) and these welding machines 12a. It is comprised of a source power source PS that supplies power to the welding machines 12a1 to 12a, and robot controllers 14a1 to 14a1 that output welding start commands including energization time specifications to the welding machines 12a1 to 12a. In this case, welding power is supplied from the original power source PS to the welding machines 12a1 to t2an via the power line L, respectively. Moreover, the welding machine 12a
! The terminals 12ah to 12ah are connected to each other by signal lines L that transmit and receive status signals S1 to S7 regarding the energized state, energized standby state, and non-energized state.

Note that the energized standby state here refers to the robot controller 1.
This refers to a state in which a welding start command is input from 4a1 to 14a, but the energization state has not yet been reached. Further, the de-energized state refers to a state in which a welding start command is not input and the welding machine is in a stopped state.

Here, the welding machines 12a1 to 12a are each composed of the same components, and therefore, to avoid complexity, only the welding machine 12a1 will be described in detail below, and the other welding machines 12a2 to 12a. will be briefly explained.

This welding machine 12a1 is substantially composed of a welding control section 16a1 and a welding gun 18al as a welding means. Then, the robot controller 14a1 sends a welding start command signal C to the welding control unit 16a1 including the energization time designation.
1 and the welding control unit 16a. The welding completion signal C0 is received from the welding completion signal C0.

The welding control section 16a1 includes a simultaneous energization prevention device 20a1.
and a control circuit 22a, which operate in cooperation as follows. In other words, simultaneous energization prevention equipment 2
0a1 is the other welding machines 12a2 to 12a. , welding control sections 16a2 to 16a. Status signals S2 to S indicate the energized state, energized standby state, and non-energized state in binary levels.
．． , will be described later? Start command corresponding signals CY2 to cyrt are introduced via the signal line L to detect the number of welding machines in the energized state, energized standby state, and de-energized state, and this number and the number of welding machines are output from the robot controller 14a. It operates to determine the energization order of the welding machines 12a1 based on the welding start command signal C1, and to determine whether or not energization is possible based on the preset number of machines that can be energized simultaneously. Here, the start command corresponding signals C■ to CYn are the welding start command signal C1.
This is a signal output corresponding to co to co.

The control circuit 22a1 is composed of a welding timer 24a1 and a welding current supply circuit 26a1. Among these, welding timer 24a. is the robot controller 14a1
A welding start command signal CI is introduced from the welding start command signal CI, and an energization request signal C, as a response signal to the welding start command signal CI, is output to the simultaneous energization prevention device 20a1, while a welding completion signal C. is output to the robot controller 14a1 and the simultaneous energization prevention device 20a.

On the other hand, under the control of the welding timer 24a1, the welding current supply circuit 26a1 converts commercial alternating current as welding power supplied from the source power source PS of the welding system 10 into direct current, and further converts it back into high-frequency alternating current, and performs welding. It is supplied to the gun 18a1.

Welding gun 18a is comprised of a welding transformer Trl, a rectifier (not shown), and a pair of welding electrodes ELI. The welding gun 18a1 introduces high frequency alternating current from the welding current supply circuit 26a, and transforms it by the welding transformer Trl. Press,
The rectifier converts the electric power into direct current, and the converted electric power is supplied to a pair of welding electrodes ELL which press and hold the material to be welded W to perform welding.

FIG. 2 shows the detailed structure of the simultaneous energization prevention device 20a1 in the welding control section 16a+. In addition, other simultaneous energization prevention devices! 20a2 to 20al have the same configuration as the simultaneous energization prevention device 20a1.

The simultaneous energization prevention device 20a1 includes an energized state number detection unit 28a, a simultaneous energization priority setting unit 29a. and,
Energization order determining unit 30a, and number of devices that can be simultaneously energized setting unit 3
2a1, an energization determination section 34a, and a status signal transmission section 36a. The energized state number detecting section 28a is connected to the state signal transmitting sections 36a2 to 36a. which constitute the other welding machines 12a2 to t2ah. to status signals S2 to S.

is introduced to detect the number of welding machines in the energized state (high level), the number of welding machines in the energized standby state H, or the number of welding machines in the de-energized state (low level), and determine the energization order determining unit 30a. It is output as a detection signal Sk.

In the simultaneous energization priority setting section 29a1, energization priorities are set in advance when welding start commands are input to a plurality of welding machines at the same time, and the energization priority determination section 30a,
A signal St related to the energization priority (hereinafter referred to as a priority signal) is output to the energization priority level.

The energization order determination unit 30a1 receives the priority order signals S,
and the welding start command signal C1 from the robot controller 14a and the number of energized units detected 928a. The energization order of the welding machine 12a is determined by introducing the detection signal S from the welding machine 12a, and the signal SP (hereinafter referred to as
An energization priority determining signal) is output to the energization propriety determination section 34a1.

The number of welding machines 12a to 12ah constituting the welding system IO that can be energized simultaneously is set in the number setting unit 32a that can be energized simultaneously, and this setting is set in the energization permission determination unit 34a1. Signal SN related to the number of units
(hereinafter referred to as the set number signal).

The energization determination unit 34a1 receives the energization priority determination signal SP.
and the welding timer 24 based on the set number signals S and I.
a. A signal SY (hereinafter referred to as the energization propriety signal) is output to the energization mode.

Further, the status signal transmitter 36a1 is configured to control the welding timer 24.
A state signal Sl is received from a1 and outputted via a signal line L to energized state number detection units 28a, 28a, which constitute simultaneous energization prevention devices 20a2 to 20an of other welding machines 12a2 to 12a6.

The welding system according to this embodiment is basically configured as described above, and its operation and effects will be explained in detail below.

FIG. 3 shows a flowchart illustrating the general operating procedure of the welding system 10 according to this embodiment.

Therefore, first, from the robot controller 14a, the simultaneous energization prevention device 20a + of the welding control section 16a1 and the welding timer 24a . A welding start command signal C1 including initial pressurization time and energization time designation is output to (STP1a). In response to this welding start command signal C+, the welding timer 24a+ outputs the welding transformer Trl.
An energization request signal C indicating whether or not to energize is outputted to the energization order determination unit 30a1. This energization request signal CR
Using this as a trigger, a start command corresponding signal CY+ is outputted from the energization order determining unit 30a1 to the other welding machines 12a2 to 12a7 (STP1b).

In this case, other welding machines 1 are detected in the energized state number detection unit 28a1.
2a2 to 12a. , control circuits 22a2 to 22a7 of
The state signals S2 to S indicate whether the current is in the energized state (high level), the energized standby state, or the non-energized state (low level).

and start command corresponding signals CY2 to CY, are introduced.

Then, in the energized state number detection unit 28a, the energized state, collar, energized standby state or non-energized state of the other welding machines 12a2 to 12a, . The number of devices in the state is determined, and a detection signal S related to these numbers is output to the energization order determining section 30a1 (STP2).

Next, the energization order determining unit 30a. The energization order is determined at (STP3).

FIG. 4 shows a detailed flowchart regarding the determination of the energization order in step 30. In this case, first, the energization order determining unit 30a. reads the contents of the welding start command signal CI introduced from the robot controller 14a and the detection signal SK introduced from the energized state number detection unit 28a twice to accurately read them (STP I). Next, it is determined whether there is a welding machine in an energized state (STPn)
.

If no signal related to the energization state of the other welding machines 12a2 to 12ah is detected, the welding machine 1
The energization order determination signal S of 2a1 is set as the first order (STP
III) The energization order signal of the first order is output to the energization propriety judgment unit 34a1 (STP■).

On the other hand, if a signal related to the energization state is detected in step (2), it is determined whether the generation timing (rising edge) of the detection signal and the generation timing (rising edge) of the welding start signal are the same (STPIV). If they are not simultaneous, the value obtained by adding 1 to the number of other welding machines that are energized at the timing when the welding start signal is generated is used as the energization priority determination signal S p (
S T P V ) is output to the energization determination unit 34a1 (STP■>).

On the other hand, if there is a signal change at the same time, the energization order of the welding machine 12a is determined based on the priority of simultaneous energization of the welding machine 12a1 in the entire welding system and the number of welding machines that are currently energized. is determined (STPVI)
, the energization order determining signal S, is the energization possibility determining unit 34a.
1 (STP■). Here, the priority order for simultaneous energization refers to the order of priority when energizing multiple welding machines 12 constituting the welding stem.
a, to 12a. Refers to the order of priority of energization when welding start command signals are input at the same time.

In this way, the energization order determining signal S, is output to the energization propriety determination section 34a1.

In this case, a signal SN for the number of devices that can be simultaneously energized is introduced into the energization permission determination section 34a+ from the number setting section 32a1 for the number of devices that can be energized simultaneously, and the welding is performed based on the energization order determining signal S and the set number signal S9. A determination is made as to whether the welding machine 12a can be energized immediately, and an energization permission signal S is output to the welding timer 24a1 (STP4). That is, when the set number of units that can be energized simultaneously is exceeded, the energization enable/disable signal S, is output as an energization/disable signal (for example, a low level signal) (STP7), and when the number is less than the set number, the energization enable signal (for example, a high level signal) is output. ) is output (STP5).

Here, the welding process executed by the welding machine 12a1 in step 6 when the energization enable signal S, as the energization enable signal is output, will be explained with reference to the time chart shown in FIG. In this case, time T. When the welding start command signal C1 (see FIG. 5a) is input at , an energization enable/disable signal S, (see FIG. 5b) relating to energization is output.

Therefore, at time To, the workpiece W to be welded is supported between the welding electrodes ELI of the welding gun 18a1, and initial pressure is applied between times To and T1 (see FIG. 5C). Next, the original power supply PS
from welding current supply circuit 26a1 and welding transformer TrI
Welding current is applied to the welding gun 18a through the welding gun 18a. (see FIG. 5d, time T+ point).

When welding is completed, the current supply is stopped (time T2 in Figure 5 d1).
(see point), and the material to be welded W is held under pressure until it solidifies (see Fig. 5e). Then, at time T3, the pressure retention by the welding gun 18a is released, and a welding completion signal C6 is output (see FIG. 5f). In this embodiment, the status signal S1 becomes a signal related to the energized state (high level) corresponding to the gun pressurization time, as shown in FIG. 5g.

When the welding process in step 6 is completed, a welding completion signal C0 is output from the welding timer 24a1 to the robot controller 14a1 (STP10), and this welding completion signal C. The energization order determining unit 3 at the rising edge of
The data held in 0a1 and status signal transmitter 36a1 is rewritten (STPII). That is, when the welding completion signal C8 is input, the energization order determining unit 30a receives the next welding start command signal C1 from the robot controller 14a1 and energizes the other welding machines 12a2 to 12an from the energization state number detection unit 28a1. A detection signal Sk related to the number of welding machines in the energized standby state or in the de-energized state is introduced, and a state is entered in which a new energization order of the welding machines 12a1 is determined. Further, the status signal transmitter 36a1 sends a welding completion signal C. When is input, the next welding start command signal C
1 is the welding timer 24a. If no input is received, a state signal S1 relating to a non-energized state is output.

On the other hand, a low-level energization enable/disable signal S as a energization/disconnection signal
, is input to the welding timer 24a, the welding current is not supplied to the welding gun 18a1, and the welding timer 24a is inputted to the welding timer 24a.
a, outputs a status signal S, indicating that the welding machine 12a is in the energized standby state, to the status signal transmitter 36a1 (S
TP8), from the energization state signal transmitter 36a1 to other welding machines 12a2 to 12a. A status signal S related to the energization standby state is output to the simultaneous energization prevention devices 20a2 to 20a, . . . (STP9). In this case, again, the welding start command corresponding signal CY
2 to C. and enters a state of receiving status display signals S2 to Sh.

According to this embodiment, the welding machine 12a. Welding start command signal C of the welding machine 12 a . and energization information including the welding start command of the other welding machine 12 a . and other welding machines 12a2 to 12a. When a welding start command is input at the same time, a determination is made as to whether or not the welding machine can be energized based on a predetermined energization order for simultaneous energization of the welding machines 12a1 and a predetermined number of units that can be energized simultaneously, and the energization order is also determined. is determined. Therefore, since the system is always energized within the allowable set number of welding machines, appropriate power is supplied to each welding machine without exceeding the supply allowable power, and a reliable welding process is performed.

Next, in order to further facilitate understanding of the present invention, the number of welding machines constituting the welding system 10 according to the present embodiment is set to five, and these five welding machines, for example, reference numeral 1
2 a. Figure 6 shows the case where the simultaneous energization priority order when welding start commands are simultaneously input to the welding machines of 12as to 12as and the number of machines that can be energized simultaneously in the welding system consisting of 5 machines are set as shown in Table 1. Time table 1 shown in Figure 1 First, from time t0 to just before t1, welding start command signals C1 to Cs are not output from robot controllers 14a1 to 14a5, and welding machines 12a1 to 12a
, are all in a low level non-energized state. In this case, the energization determination unit 34 shown in FIG.
a, to 34a, to welding timer 24a. ~24as
The energization enable/disable signals S▼1 to S▼5 outputted to the terminals are also low-level energization disable signals.

Next, at time t1, the robot controller 14a
1 and 14a3 to welding start command signals C1 and C, (
When a high level) is output, the simultaneous energization prevention device 20a
, simultaneously receives the welding start command signal C and the status signal S3 corresponding to the welding start command signal C3, while the simultaneous energization prevention device 20a3 receives the welding start command signal C3. C, and the status signal S1 corresponding to the welding start command signal C1 are received at the same time.

In this case, the reading of the signal in the energization order determining section is performed twice in order to ensure the accuracy of the reading, as shown in step (2) of the flowchart of FIG. 4 described above. In such a state, the energization order determining unit 30a1
In step 30a3, the judgment in step (2) is established, and the judgment in step (2) is made. In this case, welding start command signal C+
, Cs and the detection signal Sk are at high level at the same time, the process of step (2) is performed.

That is, in this case, as can be understood from Table 1, the welding machine 12a has a higher priority in simultaneous energization than the welding machine 12a3, so the welding machine 12al has the first energization priority and welding is performed. The machine 12a3 has the second energization order.

Therefore, the judgment process in the fourth step of the flowchart shown in FIG.
Performed in 3. As mentioned above, since the number of units that can be energized at the same time is three, which of the enable/disable determining units 34a, 34a3
The energization enable/disable signals SYI and SY3 relating to whether energization is possible are introduced into the welding timers 24a1 and 24a3 constituting the control circuit 22a1. Energization enable/disable signal SY
I, syt). As a result, welding work by welding guns 18a and welding guns 18a3 is started.

Next, at time t2, as shown in FIG. 6b, a welding start command signal C2 is sent from the robot controller 14a2.
is output to the simultaneous energization prevention device 20a2 of the welding machine 12a2. In this case, the simultaneous energization prevention device 20a2
, from the energized state number detection unit 28a2 to other welding machines 12a.
1 and 12a3 to 12a5 status signals S1 and S
3 to S, are read, and a detection signal S, related to the energized state or non-energized state, is introduced into the energization order determination unit 30a2. Here, the energization order determination unit 30a2 determines that the simultaneous energization start command has not been input based on the determination in step (2) of the flowchart shown in FIG.
a. The energization possibility judgment unit 3 sets the energization priority signal of 3 to the 3rd place.
Introduced into 4a2. Since the number of welding machines that can be energized at the same time is three, the energization propriety determination unit 34a2
An energization permission signal SY2 (see FIG. 6b) indicating that a2 may be energized is output to the welding timer 24a2. As a result, welding work on the workpiece W2 by the welding gun 18a2 is started.

Next, at time t3, the robot controller 14a
4 and 14a output welding start command signals C4 and Cs to the welding machines 12a4 and 12a (see FIG. 6dSe).

In this case, the simultaneous energization prevention devices 20a4 and 20a each determine the energization order as described above. In other words, the welding machine 12a is ranked fourth in the energization order, and the welding machine 12a5
is designated as the fifth place in the energization order. This energization priority determination signal SP is introduced into the energization propriety determination sections 34a and 34a, respectively. Since these energization order numbers are larger than the number of devices that can be simultaneously energized (3), the energization determination units 34a4 and 34a send the energization capability signal (low level) regarding energization to the welding timer 24a, 24a, Output to.

As described above, in the welding system according to the present invention, if welding command signals exceeding the number of welding units that can be energized simultaneously are input to the welding system, the energization is prevented, so welding with one degree less than the supplied current is possible. It will be appreciated that this will not cause any failure or shutdown of the welding system.

Next, at time t4, when the welding work by the welding gun 18a is completed (see FIG. 6a), the welding operation shown in FIG.
A welding completion signal as shown in C. is simultaneous energization prevention device 2
0a. is introduced into the status signal transmitter 36a1 that constitutes the. The signal is introduced into simultaneous energization prevention devices 20a2 and 20a5 that constitute the welding system. In this case, the energization order of the welding machine 12a2 goes from the second rank to the first rank, and the energization rank of the welding machine 12a3 goes from the third rank to the second rank.
The energization order of the welding machine 12a changes from the fourth to the third. Therefore, the energization determination unit 34a4 of the welding machine 12a determines that energization is possible, and the energization capability signal SY4 indicating whether energization is possible is sent to the welding timer 24.
The welding process of the welding gun 18a4 is started by introducing the welding gun 18a4.

On the other hand, the energization order of the welding machine 12a5 changes from the 5th rank to the 4th rank according to the energization rank determination unit 30a, but since the number of welding machines that can be energized is 3, the determination process in the energization availability determination unit 34as is negative. Still maintains power-on standby state.

Next, at time t, the welding process in the welding machine 12a3 is completed, and a welding completion signal C0 is sent to the status signal transmitter 36.
a, this information is transmitted via communication line L to other welding machines 12a1 to 12a and 12a5. As a result, the welding machine 12a2 is placed in the first order of energization.
Although the order remains the same, the energization order of the welding machine 12a4 is second.
The energization order of the welding machine 12as is set as the third order.

Therefore, in determining whether or not the welding machine 122s can be energized, it is determined whether the welding machine 122s can be energized, and the welding machine 12a starts the welding process.

Then, at time t6, the robot controller 1
Welding start command signal C is sent from 4a1 to the welding machine 12a port.
, is introduced. In this case, the welding machines 12a2, 12a, 12a are energized in the first order.
, the second, and the third do not change.

By the way, the welding machine 12a. Since the energization order has been currently reset and no energization order has been assigned, a new energization order is determined at time t6. In this case, welding machine 12
a. The energization order is set to the fourth order. Therefore, the energization determination unit 34a. The determination process at is negative, the status signal S1 is in a de-energized standby state, and the welding gun t8
Welding by a + is not started.

Next, we will consider the case where the welding work by the welding machine 12a2 is completed at time t''. In this case, as is easily understood, the energization order of the welding machine 12a4 is changed from the second to the first. The energization order of the welding machine 12a, is set from the third rank to the second rank, and the energization order of the welding machine 12a, is set from the fourth rank to the third rank.Therefore, the welding machine t2a + is the energization possibility judgment unit. The determination at step 34a+ is determined to be acceptable, and the welding process using the welding gun 18a is started.

Next, at time t, all welding operations in the welding machines 12a, 12a, and 12as are completed. As a result, the welding machine 12 constituting the welding system 10
All of a1 to 12a5 are de-energized.

Note that in this embodiment, after the welding start command signal is output, the welding gun is kept energized from the time when it starts initial pressurization to the time when it ends pressurization maintenance, but this is not limited to this. Needless to say, it is also possible to control the period during which the welding current is supplied after the welding pressure (see FIG. 5d) as an energized state. In this case, the energization standby time is shortened and the welding system can operate at a higher speed.

[Effects of the Invention] As described above, according to the present invention, in a welding system consisting of a plurality of welding machines, energization priority is given when the number of welding machines that can be energized simultaneously and a welding start command related to simultaneous energization are simultaneously input to the welding machines. The ranking is set. Therefore, it is possible to limit the number of welding machines that can be energized at the same time to within the number that can be energized at the same time, thereby preventing welding defects or welding machine stoppages due to insufficient power supply. It is possible to construct a highly reliable welding system.

The preferred embodiments of the present invention have been described above. Although the present invention is not limited to this embodiment, it goes without saying that various improvements and changes in design can be made without departing from the gist of the present invention.

[Brief explanation of drawings]

Fig. 1 is a block diagram of the welding system according to the present invention, Fig. 2 is a block diagram showing the detailed configuration of the simultaneous energization prevention device in the welding system shown in Fig. 1, and Fig. 3 is shown in Fig. 1. A time chart explaining the welding process of the welding system. Fig. 4 is a flowchart for determining the energization order in the energization order determining section in the simultaneous energization prevention device shown in Fig. 2. Fig. 5 is a welding process shown in Fig. 1. Figure 6 is a diagram explaining the relationship between the gun pressurization time and other signals, and Figure 6 is a time chart explaining the operation when the number of welding machines configuring the welding system shown in Figure 1 is five. be. 10... Welding system 12a, ~12a1... DC resistance welding machine 14a,
~14ah...Robot controller 16a, ~t6
ah...Welding control parts 18a1 to 18a7...Welding gun 20a. ~20a. ...simultaneous energization prevention device 22
a, 24a, 26a 28a 29 a. 30a 32a 34a1 36a1 ~22a. ~24a. ~26ar1 ~28a. ~29a. ~3oah ~32ah ~34a. ~36ah... Control circuit... Welding timer... Welding current supply circuit... Energized state number of units detection section... Simultaneous energization priority setting section... Energization order determining section... Number of units that can be energized simultaneously Setting section... Energization availability judgment section... Energization status signal transmission section

Claims (1)

[Claims] (1) Consisting of a plurality of welding machines, the welding machines mutually transmit and receive status signals related to the energized state, de-energized state, and energized standby state, and also respond to the status signals and the welding start command from the welding start command means. A welding system that performs welding by energizing a welding gun that constitutes the welding machine,
The welding machine has at least a simultaneous energization priority setting section when a welding start command is input simultaneously, a simultaneous energization possible number setting section, and an energization propriety determination section, and the energization propriety determination section is configured to simultaneously energize the welding machine. When a welding start command exceeding the possible number of units is input, the energization priority is determined based on the priority determined in the simultaneous energization priority setting section, and simultaneous energization is possible as set in the number of simultaneous energization possible units setting section. A welding system characterized by controlling the number of simultaneously energized units to within the number of units.