Urgent! What should I do if the welding arc interferes with the controller of the stepper motor

We have also encountered a similar situation, welding and other work to the PLC interference, sometimes the motor starts suddenly, encountered workers are changing the tool, the safety hazard is very large, the manufacturer to help deal with it, summarized as follows, 1 The original data connection is replaced with a shielding function, it is simple to say that it is like a wired feeder, 2 The machine is uniformly laid with grounding, connected to the earth, especially the electrical shell, 3 part of the power supply uses an isolated power supply, which can generally solve the problem. The above methods can be referred to.

Welding machine input line, output line, stepper motor.

Cables. All are shielded cables.

Usually TIG welding.

When tungsten argon arc welding adopts high-frequency arc welding, high-frequency signals will interfere with the normal operation of some electrical appliances.

Using shielded cables is the only way to solve this problem.

Interference is very troublesome, the isolation transformer has little effect, only the controller shell is uniformly and reliably grounded, and all signal cables are shielded.

The isolation arrangement of the electrical cabinet, the signal line is shielded with twisted pair, and the electromagnetic ring can reduce the interference to a certain extent.

DC tungsten argon arc welding machine, stepper motor interference caused by high-frequency arc striking.

It can turn off the high-frequency arc striking of tungsten argon arc welding, and the contact arc striking is adopted. Use a carbon rod or other conductive items to place between the tungsten electrode and the workpiece, use resistance heat to preheat the tungsten electrode, and then quickly remove the carbon rod, similar to scratching the arc, ignition welding arc can avoid high-frequency interference by normal welding, and the tungsten electrode loss is also small.

The control stepper motor driver controls the stepper motor by controlling the pulse, and if the control pulse bandwidth of the driver is too wide or the wiring is unreasonable, the control pulse will be disturbed. TIG welding produces a large electromagnetic interference signal when the arc is started.

TIG welding has a high-pressure arc starting pulse.

Because the general stepper motor and driver shell are not magnetically shielded with aluminum, titanium and magnesium alloy shells, they cause interference to the highly sensitive receiver system, make it unable to work, and pollute the power supply, cause the single-chip microcomputer and the host computer of the control system to be unable to communicate, and cause the single-chip microcomputer to crash in serious cases, and cause difficulties to normal use, so the interference problem must be solved.

The following measures can be taken to address this:

a Power filter is installed to reduce the pollution of AC power supply.

b "One point grounding" principle. Connect the ground of the power filter, the driver PE (ground) (the driver is insulated from the chassis baseplate), the control pulse pulse- and the direction pulse DIR-short lead-out wire, the motor grounding wire, the cable protection sleeve between the driver and the motor, and the driver shield wire to the grounding post on the chassis wall, and require good contact.

c. Try to increase the distance between the control line and the power line (L, N) and the motor drive line (U, V, W) to avoid crossing. For example, when we are dealing with two drive mounting positions in the same chassis in a dual-axis drive system, one drive nameplate is facing forward and the other is facing backwards, and the structural arrangement makes these leads as short as possible.

d Use shielded wires to mitigate external interference with oneself or oneself (power cord) interference from the outside world.

After the above treatment, the system works reliably.

Is that okay?

Is that okay?

1.Increase the distance between the PC and the controller and the motor;

Do not use the same power supply as the motor driver, or add a power filter;

3.Finishing wiring, control lines and communication lines use shielded cables.

4.Check and optimize the program.

1. If the energizing frequency is too high and exceeds the maximum stepping speed of the stepper motor, the out-of-step phenomenon will occur.

2. In addition, in synchronous motors, when the motor load torque is greater than the torque that the motor can provide, the motor speed cannot keep up with the synchronous speed of the motor, which will also cause the phenomenon of out-of-step.

3. When changing direction, the pulse is lost, which is accurate in any direction, but as soon as the direction is changed, the deviation will accumulate, and the more times it will deviate, the more deviations.

4. The initial velocity is too high, and the acceleration is too large, which causes sometimes lost steps.

Stepper motor is a kind of induction motor, its working principle is to use electronic circuits, direct current into time-sharing power supply, multi-phase timing control current, use this current to supply power to the stepper motor, stepper motor can work normally, the driver is for stepper motor time-sharing power supply, multi-phase timing controller.

The stepper motor is out of step means that the number of steps running when the motor is running, which is not equal to the theoretical number of steps, that is to say, the stepper motor does not reach the position it should have reached according to the instructions. In the following cases, the stepper motor will lose its step.

1. The working torque of the stepper motor itself is not enough, and it does not have enough ability to drive the load.

2. The acceleration and deceleration process of the stepper motor is not sufficient, and the stepper motor loses step in the acceleration and deceleration process.

3. The power supply power of the stepper motor is not enough, resulting in the input power of the stepper motor is not enough, which causes the step loss.

4. The driving voltage of the stepper motor is not enough or the driving current is set too low.

5. The driver or controller receives signal interference.

6. The resonance of the stepper motor system causes the load capacity of the stepper motor to decrease, resulting in loss of step.

7. The signal of the driver and the controller does not match.

8. The backlash of the synchronous wheel or the reducer or the clearance error of the back and forth is not compensated in the program or the compensation value is incorrect.

9. There is a problem with the design of the control program of the system itself.

The loss of step and inaccurate positioning of the stepper motor are generally caused by the following reasons:

1. When changing the direction, the pulse is lost, which is accurate in any direction, but the cumulative deviation will be accumulated as soon as the direction is changed, and the more times the deviation will be;

2. The initial velocity is too high, and the acceleration is too large, which causes sometimes lost steps;

3. In the case of using synchronous belt, the software compensates too much or too little;

4. The motor strength is not enough;

5. The controller is disturbed and causes malfunction;

6. The driver is caused by interference;

7. Software Defects.

In some automatic control fields, the use of stepper motors still accounts for a considerable proportion, but the characteristics of stepper motors are determined.

Its use characteristics, often in the process of debugging will be found stepless motor lost step, stalled rotor and positioning inaccurate phenomenon, encountered this situation.

Don't be in a hurry, let alone deny the size of the model of the stepper motor selected, you must calmly observe and analyze the phenomenon.

Find out how to solve it!

1) The general stepper driver has certain requirements for direction and pulse signal

For example, the direction signal is determined a few microseconds before the arrival of the rising edge or falling edge of the first pulse (different driver requirements are different), otherwise there will be a pulse that runs at an angle opposite to the actual required turning, and the final fault phenomenon is manifested as more and more deviated, and the smaller the subdivision is more obvious, and the solution is mainly to use software to change the logic of the pulse or add delay.

2) Due to the characteristics of the stepper motor, the initial velocity cannot be too highEspecially when the load inertia of the belt is large, the initial velocity is recommended.

Below 1r s, the impact is small, and the impact on the system is also large if the acceleration is too large, which is easy to overshoot, resulting in inaccurate positioning;

There should be a certain pause time between the forward and reverse rotation of the motor, if not, it will cause overshoot due to too much reverse acceleration.

3) Adjust the value of the compensated parameters according to the actual situation. (Because the elastic deformation of the timing belt is large, it needs to be compensated when changing the direction).

4) Increase the motor current appropriately. Increase the driver voltage (pay attention to the optional driver) and choose a motor with higher torque.

5) Interference of the system causes malfunction of the controller or driverWe can only find a way to find the source of interference and reduce its interference capacity.

Such as shielding, increasing the separation distance, etc.), cut off the transmission path, and improve their own anti-interference ability.

The meaning of lost step.

The motor has three sets of winding, and there are three lines. Six beats: three LEDs, looped twice before returning to the starting state.

Every time the three LED lights of the three-phase flash, the stepper will also step into the wire, and the rotation flashes twice that is, the wire.

Generally, the motor is out of step because one or two phases are missing, that is to say, one of the circuits is broken (as for the motor or the controller is broken, you have to check).

Let the motor perform in a single step, that is, each step is wired forward, and each step is shaken by hand to see if it is locked. If there is a problem with which line is on when the LED is on and the motor is not locked, you can check the ones related to this line. Let's start with the machine (i.e. the motor).

Turn off all the power supply, disassemble the interface between the machine and the controller, find these three wires, and then find the 24V power cable. Turn the multimeter to the resistor, and measure these three with the 24V line one by one. Under normal conditions, there should be a resistance of ohms or so, and there are also motor resistances of large and small, in short, if the resistance of which wire is not the same as the others.

There might be a problem with that line.

If the results of the motor test are all correct, you should use the same method to test the controller.

If the result of the test is that there is a problem with the motor, follow the line you detected to test the motor. If you are lucky, if the wire is broken, you can connect it, and if you are not lucky, you will have to change the motor.

If it's a controller issue, you also follow the detected line all the way up. You can know. To solve the problem of misstep, we must first figure out the cause of the misstep, and there are many articles on this.

The actual commissioning process encountered:

1.The motor torque is not enough, and the load capacity is poor. Today, I encountered that the motor could not be dragged because the trachea was too hard, the elasticity was not good, and the deformation was difficult.

2.There is a problem with the speed curve, and the stepper motor itself works in the low-speed section, so the acceleration and deceleration should be carefully adjusted according to the different loads.

3.The voltage is too low and the response is slow. Usually under the premise of safety, a higher voltage will be much less troublesome.

4.Poor heat dissipation leads to a drop in magnetic force. The test machine is normal when the machine is cold, and the heat dissipation problem should be considered if the step loss occurs after running for a period of time.

As far as I can think of, there are two situations where an asynchronous motor can be out of sync.

1. In the lifting place, that is, driving, after the asynchronous motor is powered on, in the process of descending with heavy objects. 、

2. The asynchronous motor is under the control of the inverter, in the process of deceleration and stopping.

The load is too large, the current is not enough, and the frequency is too high.

The controller cannot control the speed of the stepper motor. The actual control of the motor speed is the host computer (the device that sends pulses), such as PLC, single-chip microcomputer and other equipment that can output pulses.

Since it is a stepper motor, it can be realized.

1. The speed of the stepper motor is determined according to the pulse frequency, and you can reverse the high-speed pulse if you forward is a low-speed pulse.

2. The stepper motor determines the rotation angle according to the number of pulses, and does not use a position sensor.

3, the same as 1,

It is possible not to use a PLC, but to use a stepper driver.

The stepper driver panel operation has the function of controlling the pulse output of the stepper motor, and there are many functions, using 10gm or 20gm as the positioning module.

The definition of a stepper motor is an open-loop control element stepper motor device that converts an electrical pulse signal into angular or linear displacement.

Therefore, there must be an electrical pulse signal to make the stepper motor rotate, and the controller and PLC give this electrical pulse signal to make the motor rotate.

The driver is a must, because it is a current amplifier, the PLC can be used, the pulse can also be sent with the step controller, it can also be programmed, and there are input and output points.

I didn't need a controller and a driver for the two-phase motor. One 12V AC power supply. The two negative poles are connected in parallel to one end of the power supply, and the other end comes out to connect to the positive phase A.

Phase A is positive, and then a 2 microfaring fan capacitor is connected to phase B. When the 12V transformer is energized, the stepper motor will spin up, and the speed is not fast.

Generally, the stepper motor and the stepper driver are matched, and the driver can be set to pulse control the stepper motor.

There are such stepper motors.

I have used such a 220V AC stepper motor, this kind of stepper motor does not need a stepper driver, the stepper pulse is based on the peaks and troughs of the AC current; This kind of stepper motor is very easy to use, and it is easier to use than ordinary AC motors (the start-stop is more stable than ordinary motors).

Stepper motors need the driver to receive pulses to rotate!

ULN2003 is already the simplest, and the simple IO current is not enough.

Yes, twist the live wire together.

No. Controllers--- drivers--- stepper motors are so that they can operate.

Some controllers can do offline programming, offline programming can be set to the forward and reverse speed, number of steps, program on the computer, pull a limit switch out, and then leave the computer and only connect the power supply.

When a stepper driver is used, stop sending control pulses to the stepper driver or stop sending an enable signal, and the stepper motor will stop. When the controller wants to stop the stepper motor from running, it is best to send a deceleration control pulse until it stops, which can reduce the overshoot of the stepper motor, and at the same time can reduce the electromotive force generated by the motor due to the emergency stop, damaging the driver. Details can be found in Innex**.