JPH0329509B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a welding machine control device that allows an operator to remotely adjust welding conditions such as welding voltage, welding current, feeding speed of consumable electrode wire, and welding speed.

When performing arc welding, it is often necessary to change welding conditions during welding due to changes in welding posture, changes in the shape of the workpiece, etc. Furthermore, in shipyards, ironworks, and the like where large objects to be welded are handled, the installation location of the welding power source and the actual work location are often far apart. In such a case,
It is very inconvenient and inefficient to go to the welding power source and switch the welding conditions every time the conditions are changed. Therefore, it is required that the operator has a welding condition adjuster on hand so that he can adjust the welding conditions to appropriate conditions as necessary. For this purpose, it is necessary for the operator to have at hand a variable resistor corresponding to each welding condition.

Conventionally, in such cases, in addition to a two-core cable that connects the welding machine body and the start/stop switch for starting and stopping operations such as welding start and end, a dedicated cable was used to connect each variable resistor and the welding machine body. It was connected with. However, in this case, it is necessary to use multi-core cables, which not only increases the incidence of disconnection accidents, but also significantly impedes work efficiency due to the need to route thick cables. Ta.

The present invention eliminates the drawbacks of such conventional devices, and
The present invention provides a welding machine control device with a welding condition remote adjustment function that does not require an increase in cables and has good operability.

FIG. 1 is a configuration diagram showing an embodiment of the present invention,
In the figure, 1 is a switch attached to the welding torch 2 or a hand-held operation box that outputs operation start and end signals such as welding start and end operations, electrode wire inching feed stop operation, and shield gas trial discharge stop operation. , 3 is a welding condition setting signal generation circuit (hereinafter referred to as a signal generation circuit) connected in series with the switch 1, and 4 is a series circuit consisting of the switch 1 and the signal generation circuit 3 connected to the welding machine main body. This is a control cable (hereinafter referred to as a cable) for connection. 5 is a discrimination circuit that divides the signal from the cable 4 into a switch welding start/end signal (hereinafter referred to as an open/close signal) and a signal from the signal generation circuit 3 when the switch 1 is closed or opened; 6 is a discrimination circuit of the discrimination circuit 5; A start/stop circuit (hereinafter referred to as a start circuit) receives the closing signal from switch 1 among the signals and outputs an operation start/end signal, and 7 receives the signal from the signal generation circuit 3 among the output signals of the discrimination circuit 5. This is a signal conversion circuit that converts into a reference signal for setting welding conditions. Further, 8 is a motor for driving an electric motor 9 when a starting signal is supplied from the starting circuit 6 to rotate a mechanically connected feeding roll 10 to feed the welding wire 11 toward the workpiece 12. This is a welding wire feeding speed control circuit, and 13 is a welding power source that supplies output current and voltage according to the output signal of the signal conversion circuit 7 to the welding torch 2 and the workpiece 12 when the starting circuit 6 outputs.

In the device shown in the figure, the output of the signal generation circuit 3 is not transmitted to the signal conversion circuit 7 and the discrimination circuit 5 before the switch 1 is closed. Signal generation circuit 3
When the switch 1 is closed after selecting appropriate conditions, the discrimination circuit 5 detects this and transmits the closing signal S of the switch 1 to the starting circuit 6, and also sends the closing signal S of the switch 1 to the signal converting circuit 7, which is set by the signal generating circuit 3. transmits welding condition signals. As a result, the signal conversion circuit 7 converts the output signal of the signal generation circuit 3 into the welding power source 13.
Convert and transmit signals suitable for

Now, if we consider the case where a welding start switch is used as the switch 1, the welding power source 13 is started by the output signal from the starting circuit 6, and the output of the signal conversion circuit 7 is applied between the welding torch 2 and the workpiece 12. Therefore, in addition to supplying welding power, a start signal is also sent to the welding wire feed speed control device 8 to control the welding wire 11.
Welding begins when the welding begins to be fed at a predetermined speed.

When using the welding start switch as switch 1, a switch for inching feed of welding wire or a switch for trial discharge of shielding gas, etc.,
It goes without saying that the output of the starting circuit 6 is connected to only these control circuits. Furthermore, when there are multiple welding conditions to be adjusted remotely, the number of signal generation circuits 3 corresponding to the number of welding conditions is provided and each is connected in series with a separate switch, and each series circuit is connected to a two-core or signal generation circuit. The discrimination circuit 5, starting circuit 6, and signal conversion circuit 7 corresponding to each switch and signal generation circuit may be provided by connecting them in parallel to a smaller number of multi-core cables than the number of multi-core cables. Furthermore, while the electric motor 9 is rotating or welding, the welding condition setting signal is often disturbed by noise generated by these operating currents, so the signal from the starting circuit 6 or the discrimination circuit 5 is used as the holding command signal h. It is desirable to maintain the output state of the signal conversion circuit 7. Furthermore, in automatic or semi-automatic arc welding that uses a welding wire as a consumable electrode, it is known that a substantially constant relationship exists between welding voltage and welding current within a range of appropriate welding conditions; Of course, the present invention can also be implemented in a so-called unified adjustment system in which both conditions are determined by a single setting signal.

FIG. 2 is a connection diagram showing a specific embodiment of the signal generation circuit 3, discrimination circuit 5, and signal conversion circuit 7, which are the main parts of the present invention. Signal generation circuit 3 is a variable resistor
The discrimination circuit 5 consists of resistors R51 to R
53, a diode D51, a differential amplifier OP1, a relay CR, and a DC power supply E51. In addition, the signal conversion circuit 7 is connected to resistors R71 and R7.
2. An amplifier circuit consisting of an operational amplifier OP2, which converts the output of the signal generation circuit 3 to a level suitable for the welding power source 13.

In the embodiment of FIG. 2, consider the situation before the switch 1 is closed. When switch 1 is open,
Voltage e ₀ of DC power supply E51 is supplied to a series circuit of capacitor C51 and resistor R51 and a series circuit of resistors R52 and R53. At this time, assuming that the resistance values of the resistors are r51 to r53 at the positive and negative input terminals of the differential amplifier OP1, the positive input terminal has e _ip = r53/r52 + r53・e ₀ The negative input terminal has switch 1 open. If the time is long, a voltage of e _io = e ₀ is input. If r52≠0 is maintained here, e _ip <e _io will necessarily hold, and differential amplifier OP1 will have a negative output, and relay CR1 will not be excited. on the other hand,
When switch 1 is closed, the negative terminal input of differential amplifier OP1 changes from e ₀ to r ₃ /r51 + r ₃ · e ₀ (where r ₃ is the resistance value in the adjusted state of variable resistor VR3) with the time constant c51 · r ₃ (c51 is the capacitance of capacitor C51)
descend with Therefore, if r53/r52+r53>r3m/r51+r3m (r3m is the maximum value of variable resistor VR3), the signals at both input terminals of differential amplifier OP1 will be inverted to e _ip >e _ip after a while. As a result, OP1 becomes a positive output, relay CR is energized, and normally open contact CRa1 is closed. This contact CRa1 is supplied to the starting circuit 6 of FIG. 1 as an operation start signal s. Further, the signal conversion circuit 7 receives the signal from the signal generation circuit 3 from the output terminals c-d of the discrimination circuit 5, converts it to a level suitable for the welding power source 13, and outputs the signal.

FIG. 3 is a connection diagram showing a specific embodiment in which the signal conversion circuit 7 is provided with a holding function. The signal generating circuit 3 and the discriminating circuit 5 have the same structure as in FIG. 2, so the details will be omitted. The signal conversion circuit 7 includes resistors R73, R74, variable resistor VR71,
VR72, operational amplifier OP2, servo motor M7,
Lock coil L7 that locks servo motor M7
and DC power supplies E71 and E72. Here, the sliders of the variable resistors VR71 and VR72 are both mechanically connected to the servo motor M7 via a required speed reduction mechanism, and both move in conjunction with each other. When the switch 1 is closed, the output signal of the signal generation circuit 3 is supplied to the signal conversion circuit 7 and then to the operational amplifier OP2. This input signal is
This signal is added to the output voltage of the variable resistor VR71, which is a signal of opposite polarity, by the amplifier OP2, and is supplied to the servo motor M7 to rotate it. Since the servo motor M7 moves the slider of the variable resistor VR71, it stops when the input voltage and the output voltage of the variable resistor VR71 match. Since the servo motor M7 also moves the slider of the variable resistor VR72 at the same time, the output of the variable resistor VR72 has a value corresponding to the input signal. When switch 1 is closed, this closure causes the relay to be activated as described above.
Since CR is energized and the contact CRa2 is also closed, the lock coil 7 is energized by the power source E72 and locks and fixes the servo motor M7. As a result, the variable resistor VR72 is also fixed, and as a result, the signal corresponding to the output signal of the signal generating circuit 3 is held. The input signal to the signal conversion circuit 7 is supplied for the first time when the switch 1 is closed, but from the time the switch 1 is closed until the output is held by the lock coil L7, the capacitor C5
1. Stability of operation is ensured by delaying with a delay circuit consisting of a variable resistor VR3. Note that it is desirable to have a structure in which power supply to the servo motor is cut off when the lock coil is excited.

The signal conversion circuit 7 having a holding function is not limited to one configured by combining an operational amplifier and a servo motor as in the example shown in FIG. Any device that holds a signal can be used, and even known sample-and-hold circuits can be used. Further, the signal generation circuit is not limited to one that supplies an analog signal using a variable resistor, but may also be a variable frequency oscillator. In this case, a frequency/voltage converter is installed in the discrimination circuit 5 or the signal conversion circuit 7. By providing this, the purpose of the subsequent circuit can be achieved with a configuration substantially similar to the example shown in FIG. 2 or 3. Furthermore, the signal conversion circuit 7 can also be changed from one that handles analog signals to one that handles digital signals.

FIG. 4 is a connection diagram showing an embodiment when the signal conversion circuit 7 having a holding function is digitized, 74 is a comparator, and 75 is a connection diagram that corresponds to the input signal to the up/down switching signal input terminal I. 76 is a D/A converter for converting the count output of the up-down counter 75 into an analog value. Further, 78 is a clock pulse oscillator, and 77 is an AND gate. One input of the AND gate 77 is connected to a series circuit including a resistor R75 and a DC power source E73, and this series circuit is further short-circuited by the output of the discrimination circuit 5. The output of the pulse oscillator 78 is input to the counter 75 only when the switch 1 is open.
Also, OP3 is an amplifier installed as necessary.
The output of the D/A converter 76 is converted to be suitable for the next stage control circuit. In the circuit shown in Fig. 4, during the predetermined delay time from when switch 1 is closed until the holding command signal short-circuits input terminals _h1 and _h2 , the voltage input between input terminals c and d is is compared with the output of the D/A converter 76 in a comparator 74. The comparator 74 outputs a positive logic signal when the C terminal voltage is greater than the output of the D/A converter 76, and conversely, a negative logic signal when the output of the D/A converter 76 becomes greater than the C terminal voltage. I of the counter 75
Supply to the terminal. Depending on the sign of the input signal to the I terminal, the counter 75 counts up the clock pulses to the C terminal when it is a positive input, and down counts when it is a negative input. When both input signals of comparator 74 are equal, the counter stops counting. AND while terminals h ₁ - _{h 2} are open.
One input terminal of the circuit 77 is connected to a DC power supply E73.
Since the voltage is supplied, the pulse oscillator 78
The output pulse of is supplied to the C terminal of the counter.
The output of the D/A converter 76 is also output to the amplifier OP3.
The signal is supplied to the output terminal via the welding power source and the welding wire feed control device as a welding condition signal.
If the input terminals h ₁ and _{h 2} are short-circuited, the AND circuit 77
One input of is grounded and closed, and the counter stops because the input to the C terminal is cut off regardless of the sign of the input signal at the I terminal. As a result, D/A
The output signal of the converter 76 will maintain the value immediately before the terminals h ₁ -h ₂ were short-circuited.

As described above, in the present invention, a signal generation circuit for setting welding conditions is connected in series with a switch that commands welding start, welding wire inching, etc., and both signals are transmitted using a common cable. Since both signals are differentiated on the welding machine's main body and used separately, the welding conditions can be adjusted by the operator away from the welding machine, and the number of cables can be reduced. A device with excellent workability can be obtained without causing any increase in the number of units.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention,
2 and 3 are connection diagrams showing specific embodiments of the signal generation circuit, discrimination circuit, and signal conversion circuit, which are the main parts of the present invention, respectively, and FIG. 4 is a connection diagram showing another embodiment of the signal conversion circuit. It is a connection diagram which shows an example. 1...Switch, 3...Signal generation circuit, 5...
Discrimination circuit, 6... Starting circuit, 7... Signal conversion circuit, 74... Comparator, 75... Up/down counter, 76... D/A converter, 78... Oscillator.

Claims (1)

[Claims] 1. A switch that is installed outside the welding machine body and outputs operation start and end signals such as welding start and end, wire inching start and stop, shielding gas discharge and stop, etc. a welding condition setting signal generating circuit provided externally for setting predetermined welding conditions; a control cable connecting a series circuit of the switch and the welding condition setting signal generating circuit to an input terminal of the welding machine main body; A discrimination circuit that divides the signal input to the input terminal of the welding machine main body when the switch is closed into an operation start/end signal and a welding condition setting signal, and an activation circuit that receives the operation start/end signal as input and outputs an operation start/end signal. A welding machine control device comprising a stop circuit and a signal conversion circuit that receives the welding condition setting signal as input and outputs a welding condition setting reference signal.