JPS6247627B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an arc welding power source,
In particular, it is characterized by the structure of the reference signal source of an arc welding power source that controls the output in accordance with the reference signal.

In an arc welding power source, generally, as shown in FIG. 1, a power source 101 with substantially constant voltage characteristics, such as an AC power source that is appropriately stepped down, is connected to a magnetic amplifier, thyristor, etc.
Variable impedance element 10 such as a transistor
2, this output is detected and the effective impedance of the variable impedance element 102 is controlled in accordance with the output signal of the reference signal source 104 that determines the output voltage or output current to obtain the desired output. There's a lot to gain. FIG. 1 shows an example in which the signal from the reference signal source 104 and the value of the output 103 are compared by a comparator 105, and the variable impedance element 102 is controlled based on the difference.

[Conventional technology]

Conventional reference signal source 1 of such an arc welding power source
As for 04, supply adjustable DC voltage or
Alternatively, specialized circuits designed to generate a specific pattern of reference voltage signals that vary according to some defined sequence have been used.

FIG. 13 is a connection diagram showing an example of a conventional device constructed in this manner (device described in Japanese Patent Application Laid-open No. 71246/1983). This figure shows the connection of the reference signal source of the conventional device, and the overall configuration of the welding power source is the same as that shown in FIG. 1 shown above. 13th
In the figure, 201, 202, and 213 are DC power supplies, each connected to the polarity shown in the figure. 2
03, 204, 214 are variable resistors, 205 is a changeover switch, 206, 214, 215 are resistors,
207 is a capacitor, 208, 209, 210 are operational amplifiers, and 211, 212 are diodes. Here, the operational amplifier 208 is the capacitor 207
The operational amplifier 209 compares the output of the integrating circuit with the output V ₂ of the DC power supply 213, and the output of the integrating circuit is determined as the DC power supply 2.
It is a comparator that generates a positive output when the output is greater than the output V ₂ of 13, and a negative output when it is opposite.The operational amplifier 210 receives the output of the integrating circuit and the ground potential (zero) as input, and outputs the output of the integrating circuit. This is a comparator that produces a positive potential output when is greater than zero, and produces a negative potential output when it is less than zero.

Assume now that the variable resistors 203 and 204 are adjusted so that their outputs are +e ₁ and -e ₂ , and that the selector switch 205 is on the (a) side in the figure before welding starts. At this time, the operational amplifier 208 has a positive voltage +
e ₁ is input, and its output terminal receives the integral output e ₀ = -1/CR∫e ₁ dt (where C is the capacitance of the capacitor 207 and R is the resistance value of the resistor 206). Occur. When this negative output appears slightly, operational amplifier 210 immediately produces a negative output,
This negative output is returned to the input side of operational amplifier 208 via diode 212. This negative output cancels out the input signal of operational amplifier 208 to make it negative, and operational amplifier 208 integrates this negative input to generate a positive output. Due to the positive output of operational amplifier 208, the output of operational amplifier 210 also becomes positive, but since this positive output is blocked by diode 212, the input of operational amplifier 208 is again connected to the positive output of variable resistor 203 (+e ₁ ) and return to the initial state. In this way, the output e ₀ of the operational amplifier 208 will go back and forth between zero, but if the amplification factor and response speed of the operational amplifier 210 are made sufficiently large, the output of the operational amplifier 208 will be kept at approximately zero. It turns out. Next, when the changeover switch 205 is switched to the (b) side in the figure at the start of welding, the output -e ₂ of the variable resistor 204 is supplied to the operational amplifier 208. Operational amplifier 208 integrates this input voltage and calculates e ₀
Generates a positive output of =-1/CR∫e ₂ dt. At this time, the output of the operational amplifier 210 is blocked by the diode 212, so there is no effect, while the operational amplifier 209 has its positive input terminal voltage e ₀ and the DC power supply 21
3 and generates _a positive signal when e ₀ >V ₂ . This positive signal output cancels out the input signal of operational amplifier 208, and as the input signal is inverted to positive, operational amplifier 208 starts integrating in the opposite direction. When the output signal of the operational amplifier 208 slightly decreases from V ₂ due to this integration, the operational amplifier 209 becomes a negative output again and returns to the original state. Eventually, the output of the operational amplifier 208 is maintained at the output V ₂ of the DC power supply 213. It will be dripping.
Steady welding will continue in this state. Next, when the changeover switch 205 is switched to the (a) side upon completion of welding, the output +e ₁ of the variable resistor 203 is supplied to the input terminal of the operational amplifier 208. This positive input signal is integrated by operational amplifier 208, and its output decreases according to (V ₂ -1/CR∫e ₁ dt). When the integration progresses and the output of the operational amplifier 208 reaches zero, the state returns to the state before the start of welding, and the output is maintained at zero. The waveform of the output terminal A in the above operation is as shown in FIG. In the same figure, time t ₁ is C, R, -e ₂ and V ₂
The time t ₂ is determined by C, R, +e ₁ and V ₂
The time t ₂ is determined by C, R, +e ₁ and V ₂
Determined by. (However, C, R, -e ₂ , +e ₁ and V ₂ are as described above) Also, the maximum output voltage e is set to the maximum by the setting of the variable resistor 214.
Can be adjusted up to _V2 .

[Problem that the invention seeks to solve]

Conventional devices are configured as shown in Figure 13, an example of which is designed so that the variable resistor and changeover switch can be operated from the outside, but the rest is constructed using a printed wiring board or They are mounted on the chassis, assembled together by soldering, and housed in a control box. For this reason, it is difficult to change the basic pattern of the output voltage waveform. For example, if the pattern of the output voltage waveform is
In order to change the power supply so that it changes in two stages, large and small, as shown in Figures a and b, two systems of DC power supplies 213 are provided, 213a and 213a, as shown in Figure 16.
It is necessary to provide a changeover switch 216 as 13b for switching. For this purpose, it is necessary to change the printed wiring board itself or perform machining to newly install a changeover switch on the operation panel. Furthermore, in order to automatically switch the changeover switch 216 using a timer, it is necessary to incorporate a timer circuit into the printed circuit board and redo the wiring assembled by soldering, resulting in a major remodeling work. All of these modifications require a design engineer and specialized manufacturing staff, and require a significant amount of time and expense, so it is almost impossible to perform them every time the waveform required for welding changes. It is possible. However, in arc welding, it is necessary to set the welding method and welding conditions (current, voltage values, and changes) to appropriate values depending on the material, size, combination, etc. of the workpiece. Welding of metals and light metals requires complex changes in the output waveform, and since the manner of this change has not been established, it is usually determined by repeated trial-and-error experiments for each workpiece. be.

Conventionally, in order to meet these demands, a separate device designed to obtain output with characteristics suitable for each was prepared separately, and when performing welding, only the time setting and wave height value setting changes were placed on the panel. This was done by manipulating variable resistors, etc. Therefore, the output waveform can only be changed by changing its peak value or length of time, and it is not possible to change the output waveform to anything other than a pattern similar to the basic pattern.

[Means for solving problems]

The present invention includes, for example, a power supply 101 having substantially constant voltage characteristics as shown in FIG. 1, a variable impedance element 102 connected in series to the output terminal of this power supply, and a reference signal source 104 that determines the output voltage or current. In an arc welding power source that obtains a desired output by controlling the effective impedance of a variable impedance element in accordance with the output of a reference signal source, a start signal input terminal, a level signal input terminal, a unit signal output terminal, and an operation termination terminal are used. Slope-up, slope-down, current or voltage level setting, time control, which has signal output terminals, etc., and is configured by combining some of the following internally: an integral circuit comparator, constant voltage source, timer, flip-flop circuit, amplifier, etc. A plurality of control units with simple pattern elements such as settings are installed, and an adder is installed to add the outputs of these units. Arc welding equipped with a reference signal source that allows you to easily obtain a reference signal of any pattern without changing the internal circuit connections of each unit by simply connecting them with cords with plugs or receptacles on both ends. It provides power.

〔Example〕

2 to 5 show examples of control units constituting the reference signal source used in the present invention. Note that in each figure, the power source for driving these is omitted to simplify the explanation.

FIG. 2 is a block diagram showing an embodiment of the slope up unit 1. As shown in FIG. In the figure, 11 is an integrator;
12 is a comparator, and 13 is a reset circuit. A
is a start signal input terminal to which a start signal for starting the slow-up operation is input, and is connected to the integrator 11. B1 is a level signal input terminal to which a signal to be integrated by the integrator 11 is input, and is connected to the integrator 11. B2 is a level signal input terminal that determines the end of integration of the integrator 11, and is connected to one terminal of the comparator 12. Integrator 11
The output terminal of is connected to the other terminal of comparator 12. It is also connected to the slope up unit signal output terminal C. The output terminal of the comparator 12 is connected to the slope-up operation end signal output terminal D and also to the reset circuit 13, and the output terminal of the reset circuit 13 is connected to the integrator 11.

When the activation signal is input to the activation signal input terminal A, the integrator 11 starts integrating the input signal of the level signal input terminal B1, and outputs the integration result to the terminal C as a slope up unit signal. Integrator 1
The output of level signal input terminal B2 is compared with the input signal of level signal input terminal B2 by comparator 12, and when the two match, comparator 12 outputs a slope-up operation end signal to terminal D (and outputs it to reset circuit 13).
A reset signal is supplied to the integrator 11 to cause the integrator 11 to stop integration and return the internal state to the initial state.

At this time, if the input signal to the terminal A is not a pulsed signal but a continuous signal, the output signal of the reset circuit 13 may be configured to block the signal from the terminal A from being input to the integrator 11. In addition, in order to make the end of the slope up to the same level as the input signal of terminal B1, terminal B1 and terminal B2
Just short-circuit them and input the same signal to both.

FIG. 3 is a block diagram showing an embodiment of the slope-down unit 2. A subtracter 21 is added between the integrator 11 and the unit signal output terminal C to the slope-up unit shown in FIG. By subtracting the output from the input signal of the integrator 11, a down slope operation is performed. Terminal A and terminal B1 are connected to an integrator 11, and the integrator 11
The output terminal of the subtractor 21 is connected to the input terminal of the subtracter 21, and the output terminal of the subtractor 21 is connected to the C terminal and one input terminal of the comparator 12, and the other input terminal of the comparator 12 is connected to the input terminal of the subtracter 21. B2 on the terminal
Terminals are connected. The output terminal of the comparator 12 is connected to the D terminal and also to the reset circuit 13, and the output terminal of the reset circuit 13 is connected to the integrator 11. In the subtracter 21,
The output signal of the integrator 11 is subtracted from the input signal of the terminal B1, and the result is outputted to the output terminal C as a slope down unit signal, and is also inputted to the comparator 12. The comparator 12 compares the output of the subtracter 21 and the input signal from the terminal B2, and when they match, outputs the output to the terminal D and the reset circuit 13,
The integration operation of the integrator 11 is stopped and the down slope operation is ended.

FIG. 4 is a block diagram showing an embodiment of the level signal setting unit 3 for setting the welding voltage or current. In the figure, 31 is an adjustable DC power supply, which is connected to the output terminal E1, and is connected to the output terminal E1.
Outputs a continuous level setting signal of 1. 32 is a start signal input terminal A and a level signal input terminal B3
This is a timer connected to the start signal input terminal A.
The signal from the level signal input terminal B3 is outputted to the unit signal output terminal C for a predetermined time after the activation signal is input to the unit. If the timer 32 is capable of repeated operation, it is possible to output a level signal that changes intermittently. In addition to the general CR type timer, a timer using a mono multivibrator can also be used as this timer.

FIG. 5 shows another level signal setting unit which is a partial modification of the level signal setting unit 3 shown in FIG. The figure shows a Q of an RS flip-flop circuit 41 in which terminals B3 and E1 in FIG. 4 are short-circuited to form a terminal E2, and terminals A and G are connected to the input side.
A DC power supply 31 and a timer 32 are connected so as to be activated by a terminal output. When a start signal is input to terminal A, the DC power supply 31 starts,
A level signal is output to the level output terminal E2, and the timer 32 is activated to output a signal at the same level as the terminal E2 to the unit signal output terminal C for a certain period of time. G is a reset terminal, and the reset signal causes the flip-flop circuit 41 to return to inversion, and the terminal E
The output of 2 disappears. The timer 32 also returns.

Each of the above units has a unit structure in which each unit is assembled into a single chassis, and each terminal A, B1,
B2, B3, C, D, E1, E2, and G are each pulled out as plug-type terminals at the front of the unit, and the power terminals (not shown) for operating these are pulled out at the rear of the unit using multi-plugs, etc. . Further, if connections between each unit and an adder to be described later are made by a cord having plugs or receptacles at both ends, the pattern can be easily changed.

Next, an example will be described in which a desired pattern is obtained by combining these control units. For convenience of explanation, it is assumed that each control unit is activated when a falling signal is input to the A terminal, and each control unit is activated when a falling signal is input to the A terminal. The power source for driving the control unit is omitted.

FIG. 6 is a block diagram showing an example of the configuration and interconnection of a reference signal source to obtain an output pattern as shown in FIG. 7d using the control units shown in FIGS. 2 to 5. be. In FIG. 6, 3a and 3b are level signal setting units, which are the same as the level signal setting unit 3 shown in FIG. 1 is a slope up unit as shown in FIG. 2, and 5 is an adder for adding these respective outputs. It is convenient to use an operational amplifier as the adder because it provides excellent input/output proportionality. The slope up start signal A is connected to be input to the A terminal of the slope up unit 1, and the C terminal of the slope up unit 1 and the level signal setting unit 3b and the E1 terminal of the level signal setting unit 3a are connected to the adder 5. connected to the input terminal. Furthermore, the D terminal of slope up unit 1 is connected to the A terminal of level signal setting unit 3b, and the E1 terminal of level signal setting unit 3b is connected to slope up unit 1.
It is connected to the B1 terminal, the B2 terminal, and the B3 terminal of the level signal setting unit 3b.

FIG. 7 is a diagram showing the output pattern of each part of the reference signal source obtained in the configuration of FIG.
is the output of the E1 terminal of the level signal setting unit 3a in FIG. 6, b is the output of the C terminal of the slope up unit 1, and c is the C of the level signal setting unit 3b.
The terminal outputs d through f are the total output pattern obtained by adding the outputs of these respective units. Connect the D terminal of the slope up unit 1 to the A terminal of the level signal setting unit 3b, the E1 terminal and B3 terminal of the level signal setting unit 3b, and the B1 and B2 terminals of the slope up unit 1, respectively. The E1 terminal of the level signal setting unit 3a and the C terminals of the slope up unit 1 and level signal setting unit 3b are connected to the input terminal of the adder 5.

The level signal setting unit 3a always outputs a constant DC low voltage output _VB to the E1 terminal and inputs it to the adder 5. When the slope up unit 1 receives the slope up start signal A at the A terminal, it integrates the DC voltage output V _P at the E1 terminal of the level signal setting unit 3b and outputs the result to the C terminal. When the integration progresses and the output becomes equal to V _P , a slope up operation end signal is sent from the D terminal to the level signal setting unit 3.
It is output to the A terminal of the slope up unit 1, and at the same time it is activated, the inside of the slope up unit 1 is reset. The level signal setting unit 3b outputs the DC voltage V _P from the terminal C for a certain period of time from the time when the operation of the slope up unit 1 is completed. Adder 5 adds the outputs of level signal setting unit 3a, slope up unit 1 and level signal setting unit 3b to obtain the total output shown in FIG. 7d.

If one cord is added to connect the C terminal of the level signal setting unit 3b and the A terminal of the slope up unit 1 as shown by the dotted line in FIG. When the output disappears, the slope up unit 1 is activated again by the fall of this signal and starts the slope up operation, and thereafter these operations are repeated to obtain a total output that changes repeatedly as shown in FIG. 7e.

FIG. 8 shows the connection shown in FIG. 6 with three additional connection cords. Level signal setting unit 3a
E1 terminal and B3 terminal, level signal setting unit 3a
C terminal of and A terminal of slope up unit 1,
The C terminal of the level signal setting unit 3b and the A terminal of the level signal setting unit 3a are connected, and the other connections are the same as the solid line portion in FIG. In the connection shown in FIG. 8, the slope up unit 1 is activated after the time set by the timer of the level signal setting unit 3a has elapsed, and after the slope up operation of the slope up unit 1 is completed, the level signal setting unit 3b is activated. Level signal setting unit 3
After the set time b has elapsed, the level signal setting unit 3a is activated again. The adder 5 receives the steady voltage V _B of the E1 terminal output of the level signal setting unit 3a, the slope up output of the C terminal of the slope up unit 1, and the voltage V _P that continues for a certain period of time from the C terminal of the level signal setting unit 3b. As a result of sequentially inputting , a repeated output as shown in FIG. 7f is obtained. By preparing two level signal setting units and one slope up unit as shown in Figs. 6 to 8, three types of patterns can be easily obtained by simply changing the external cord connection.
Furthermore, by changing the external cord connection, it is possible to obtain square waves, sawtooth waves, etc.

FIG. 9 is a configuration diagram showing another embodiment. E1 and B3 terminals of level signal setting unit 3, B1 terminal of slope down unit 2, C terminal of level signal setting unit 3 and A terminal of slope down unit 2, and D terminal of slope down unit 2 and level signal setting unit. 3 and the A terminals of level signal setting unit 3.
The C terminal of the slope down unit 2 and the C terminal of the slope down unit 2 are connected to the input terminal of the adder 5. Also, the B2 terminal of the slope down unit 2 is connected to the ground potential. A constant voltage output V _P is output from the C terminal of the level signal setting unit 3 for a time set by an internal timer. When the C terminal output disappears after a certain period of time has elapsed, the slope down unit 2 is activated by the fall of this output voltage. The slope down unit 2 performs a slope down operation that gradually decreases with a time constant set by V _P , and when the output voltage reaches the ground potential of A2, the operation end signal is output to D.
The signal is input from the terminal to the A terminal of the level signal setting unit 3 to start up the level signal setting unit 3 again.
The level signal setting unit 3 again outputs the constant voltage V _P for the set time, and thereafter repeats these operations. FIG. 10 is a diagram showing the output pattern of each part of the reference voltage source obtained with the configuration shown in FIG. The total output pattern obtained by adding the outputs in the adder 5 is c.

Here, if you want to stop the downslope operation midway rather than at ground potential, use slope down unit 2.
Just apply a predetermined DC voltage to the B2 terminal of the

FIG. 11 is a block diagram showing another embodiment for obtaining a more complex output pattern. The figure shows one slope up unit 1, two slope down units 2, five level setting units 3,
1 level signal setting unit 4, 1 subtracter
In this case, four adders are used. The terminal to which welding start signal A is applied is A of level signal setting unit 4.
connected to the terminal. The C terminal of the level signal setting unit 4 is connected to the A terminal of the slope up unit 1. The D terminal of the slope up unit 1 is connected to the G terminal of the level signal setting unit 4 and also to one A terminal of the level signal setting unit 3a. The C terminal of the level signal setting unit 3a is the normally closed contact 7b ₁ of the relay 7.
It is connected to the A terminal of the slope down unit 2a through a normally open contact _7a1 , and to the A terminal of the slope down unit 2b and level signal setting unit 3d through a normally open contact 7a1. The D terminal of the slope down unit 2a is connected to the A terminal of the level signal setting unit 3b, and the C terminal of the level signal setting unit 3b is connected to the level signal setting unit 3b.
It is connected to the other A terminal of a. Level signal setting unit 3a, level signal setting unit 3
b and the C terminal of the slope down unit 2a are connected to the input terminal of the adder 5a. The E1 terminal of the level signal setting circuit 3a and the E2 terminal of the level signal setting circuit 4 are connected to the input terminal of the subtracter 6, and the output terminal of the subtracter 6 is connected to the B1 terminal and the B2 terminal of the slope up unit 1. . The E1 terminal of the level signal setting unit 3a is connected to the B3 terminal of the same unit and the slope down unit 2a.
It is connected to the B1 terminal and also connects to the slope down unit _2b via the normally open contact 7a2 of the relay 7.
Connected to B1 terminal. The E1 terminal of the level signal setting circuit 3b is connected to the B3 terminal of the same unit, and the B2 terminal of the slope down unit 2a.
connected to the terminal. The D terminal of the slope down unit 2b is connected to the A terminal of the level signal setting unit 3C.
The C terminal of the slope down unit 2b and the C terminal of the level signal setting unit 3c are connected to the input terminal of the adder 5b. The terminal E1 of the level signal setting unit 3c is connected to the B3 terminal of the same unit and the terminal of the slope down unit 2b.
Connected to B2 terminal. The output terminal of the adder 5b is connected to the B3 terminal of the level signal setting unit 3d, and the C terminal of the level signal setting unit 3d is connected to the A terminal of the level signal setting circuit 3e. The E1 terminal of the level signal setting circuit 3e is connected to the B3 terminal of the same unit. The C terminals of level signal setting units 3d and 3e are connected to the input terminal of adder 5c. The C terminal of the level signal setting unit 3e is connected to the level signal setting unit 3d.
is connected to the A terminal of the The E2 terminal of the level signal setting unit 4, the C terminal of the slope up unit 1, and the output terminals of adders 5a and 5c are connected to the input terminal of adder 5d.

7 is a relay for operating the crater filler at the end of arc welding, and the contact 7 is normally open during welding.
a ₁ , 7a ₂ , and 7a ₃ are open, and the normally closed contact 7b is closed. In the crater filler, contacts 7a ₁ , 7a ₂ , and 7a ₃ are closed and contact 7b is opened in response to the start signal. Contacts 7a ₁ , 7 due to completion of crater filler
a ₂ and 7a ₃ are opened again, and contact 7b is closed. The function of each unit is as follows. The level signal setting unit 4 determines the preheating current value and preheating time for preheating prior to actual welding. The slope up unit 1 determines the slope up characteristic for gradually increasing the current from the low current for preheating to the high current for actual welding when transitioning from the end of preheating to the actual welding. The level signal setting unit 3a determines the high current value and its duration in main welding,
The level signal setting unit 3b likewise determines the low current value and its duration. The slope down unit 2a determines the slope down characteristic for smoothly transitioning from high current to low current. The slope down unit 2b determines a slope down characteristic for smoothly transitioning the current from the main welding current to the crater filler current during crater filler. The level signal setting unit 3c determines the crater filler current and its duration at the end of the operation of the slope down unit 2b. The outputs and inputs of the level signal setting unit 3d and the level signal setting unit 3e are connected to each other, and they perform repeated operations while the input is supplied to the B3 terminal of the level signal setting unit 3d. The level signal setting unit 3d outputs the output of the adder 5b in fixed time intervals, and the level signal setting unit 3e outputs the output at a low level to allow the basic current to flow while the output of the level signal setting unit 3d disappears. Generate a signal.

Next, the operation will be explained step by step with reference to the output pattern diagram of each part shown in FIG. 1st
Figure 2 a shows the output of the E2 terminal of the level signal setting unit 4, b shows the C terminal output of the slope up unit 1, c shows the C terminal output of the level signal setting unit 3a, d shows the C terminal output of the slope down unit 2a, e is the C terminal output of the level signal setting unit 3b, f is the C terminal output of the slope down unit 2b, g is the C terminal output of the level signal setting unit 3c, h is the C terminal output of the level signal setting unit 3d, and i is the level signal. The C terminal output of the setting unit 3e, j is the output of the adder 5d.

When the welding start signal a is input to the A terminal of the level signal setting unit 4, the preheating current setting level signal a is output to the E2 terminal. When the built-in timer of the level signal setting unit 4 expires (that is, the preheating time ends) and a falling signal is input from the C terminal to the A terminal of the slope up unit 1, the slope up operation starts. At this time, the difference between the E1 terminal output V _P of the level signal setting unit 3a and the E2 terminal output a of the level signal setting unit 4 is supplied to the B1 and B2 terminals of the slope up unit 1 by the subtracter 6, and the slope is The output from the C terminal of the up-unit 1 becomes a signal b which increases from zero to (V _P -a). The signal b is (V _P −
When reaching a), a slope up operation end signal is output from the D terminal of the slope up unit 1, and is supplied to the A terminal of the level signal setting unit 3a to start it up and also to the level signal setting unit 4.
The level signal setting unit 4 is also supplied to the G terminal of the level signal setting unit 4. Level signal setting unit 3a
starts when receiving the operation end signal of the slope up unit 1 at the A terminal, and outputs the signal c corresponding to the V _P signal input from the C terminal to the B3 terminal for a certain period of time set by the built-in timer. When the C terminal output of the level signal setting unit 3a disappears after a set time has elapsed, its falling signal is input from the C terminal via the normally closed contact _7b1 of the relay 7 to the A terminal of the slope down unit 2a. The slope down unit 2a is activated upon receiving a falling signal from the A terminal, and a level signal setting unit 3b is sent from V _P to the C terminal.
It generates an output d which slopes down until V _B1 which is the output from the E1 terminal. When the C terminal output of the slope down unit 2a matches V _B1 , a down slope end signal is generated from the D terminal and the slope down unit 2a stops its operation. The output from the D terminal of the slope down unit 2a is input to the A terminal of the level signal setting unit 3b, which is activated for the time set by the built-in timer.
An output e corresponding to the E1 terminal output V _B is generated from the C terminal. When the built-in timer setting time of the level signal setting unit 3b has elapsed, the C terminal output falls, and this is supplied to the A terminal of the level signal setting unit 3a, which starts the level signal setting unit 3a again and outputs c corresponding to a certain period of time _VP . occurs. After that, the operation of V _P → down slope → V _B is repeated.

At the end of welding, when relay 7 is switched by crater filler start signal C, contacts 7a ₁ and 7a ₂ are closed,
Contact 7b opens. Therefore, the falling signal of the time end of the level signal setting unit 3a is supplied to the A terminal of the slope down unit 2b instead of the A terminal of the slope down unit 2a. Also contact point 7
_a2 , the E1 terminal output V _P of the level signal setting unit 3a is supplied to the B1 terminal of the slope down unit 2b, so the level signal setting unit 3
The falling signal at the end of time a is sent from the C terminal to contact 7a ₁
When the signal is supplied to the A terminal of the slope down unit 2b, the slope down unit 2b starts a down slope operation and generates a slope signal f at the terminal C which drops from V _P to the level V _C of the B2 terminal. Upon completion of the down-rope operation of the slope-down unit 2b, a termination signal is generated at the terminal D and is supplied to the A terminal of the level signal setting unit 3c to start it. The level signal setting unit 3c transmits a signal g corresponding to the level signal V _C supplied to the B3 terminal to the terminal C for a time set by a built-in timer.
Output to. The outputs f and g are added by an adder 5, and a signal (f+g) is supplied to the B3 terminal of the level signal setting unit 3d. Further, since the activation signal is supplied to the A terminal of the level signal setting unit 3b at the same time as the slope down unit 2b, from this time on, a signal h corresponding to (f+g) is outputted to the C terminal for a certain period of time. In addition, since the C terminal output of the level signal setting unit 3d is input to the A terminal of the level signal setting unit 3e, after the set time of the level signal setting unit 3d ends, the level signal setting unit 3e outputs a signal at the level set at the B3 terminal. Output i for a certain period of time. When the set time of the level signal setting unit 3e ends, its C terminal output is supplied to the A terminal of the level signal setting unit 3d, so that the level signal setting unit 3d is activated again and outputs the signal h. Thereafter, this process is repeated until the setting time of the level signal setting unit 3c ends and the input to the B3 terminal of the level signal setting unit 3d disappears. Adder 5c is level signal setting unit 3
d and the C terminal output of the level signal setting unit 3e are added to obtain an output (h+i). Also adder 5
a adds the C terminal outputs of the level signal setting unit 3a, level signal setting unit 3b, and slope down unit 2a to obtain the output (c+d+e). Furthermore, the adder 5d outputs the E2 terminal output a of the level signal setting unit 4, and the slope down unit 1.
C terminal output b, output of adder 5a (c+d+
e) and the output (h+i) of the adder 5c are added to obtain the total output j. Since input signals are not applied to each input terminal of the adders 5a to 5c at the same time, adders 5a to 5c may be simply configured with OR circuits using diodes or the like. However, in that case, it is necessary to fully consider the forward characteristics (voltage drop and nonlinearity) of the diode.

In the embodiment shown in FIG. 11, two types of signals are input to the A terminal of the level signal setting unit 3a and the A terminal of the level signal setting unit 3d, but these signals should be prevented from spreading to others. As shown in the level signal setting unit 3a, two A terminals may be provided, and an OR circuit may be incorporated inside the unit using a diode, a transistor, an IC, or the like. In addition, when the input of the slope down unit 2a becomes a falling signal and malfunctions when the contact 7b of the relay 7 is opened, a normally open contact _7a3 that operates at the same time is provided to short-circuit the B1 terminal and the A terminal so that the signal remains constant at all times. It is sufficient to input the level signal V _P in advance. In addition to the level signal setting units 3d, 3e and adder 5c shown in the embodiment, a chopper circuit and a constant voltage source may be combined to convert the output of the adder 5b into a pulse having a fixed component. good.

〔Effect of the invention〕

As described above, according to the present invention, in a DC arc welding power source that obtains a desired output by controlling the effective impedance of a variable impedance element connected in series with a power supply according to the output signal of the reference signal source, Multiple control units were installed for each pattern element, and the input and output terminals of each unit were plug-type terminals, and each control unit was connected externally using a cord according to the required pattern. Not only can you easily obtain reference signals of any pattern without changing the circuit connections, but you can also change them freely, so you can easily obtain output changes as you like, and each control unit Since it can be manufactured as a standard part, the quality of the device is stable and the price can be reduced, among other advantages.

[Brief explanation of the drawing]

Figure 1 is a control circuit diagram of the arc welding power source, Figures 2 to 5 are block diagrams showing examples of each control unit of the reference signal source used in the arc welding power source of the present invention, and Figures 6 and 8. , FIGS. 9 and 11 are block diagrams showing an embodiment of a reference signal source for the arc welding power source of the present invention, which is created by combining the control units shown in FIGS. 2 to 5. The figure is a diagram showing the output pattern of each part of the reference signal source in FIGS. 6 and 8, FIG. 10 is a diagram showing the output pattern of each part of the reference signal source in FIG. 9, and FIG.
13 is a connection diagram showing an example of the reference signal source of a conventional device; FIG. 14 is a line showing the waveform of the output signal of the example in FIG. 13. 15A and 15B are diagrams showing another example of the output signal waveform, and FIG. 16 is a connection diagram showing a modification example for changing the output waveform. 1...Slope up unit, 2, 2a, 2
b...Slope down unit, 3, 3a-3
e, 4...Level signal setting unit, 5, 5a~
5d...Adder, 6...Subtractor, 7...Relay for crater filler, A...Start signal input terminal, B
1, B2, B3... Level signal input terminal, C...
Unit signal output terminal, D...Operation end signal output terminal, E1, E2...Level signal output terminal, G...
...Reset signal input terminal, 11, 21... Integral circuit, 12, 22... Comparator, 13, 23... Reset circuit, 24... Subtractor, 31, 42... Constant voltage source, 32, 43... Timer, 41...Flip-flop circuit, 101...Power supply, 102...Variable impedance element, 103...Welding machine output, 1
04... Reference signal source, 105... Comparator.

Claims (1)

[Claims] 1. A power source having substantially constant voltage characteristics, a variable impedance element connected between the output terminals of the power source, and a reference signal source that determines an output voltage or current, and a reference signal output from the reference signal source. In an arc welding power source that obtains a required output by controlling the effective impedance of the variable impedance element in accordance with A plurality of control units each having one or more functions of slope up, slope down, power or voltage level setting, and time setting, each having a terminal, a unit signal output terminal, and an operation end signal output terminal. , a plurality of cords having plugs or receptacles at both ends for interconnecting input and output terminals of each of the control units according to a desired output voltage or output current pattern; An arc welding power source comprising an adder that adds outputs from output terminals to obtain the reference signal.