Fault diagnosis of automation equipment

Power supply, including the power supply of each equipment and the power supply of the workshop, that is, all the power supplies that can be involved in the equipment.

Air source, including air pressure source required by pneumatic device.

Hydraulic source, including the working condition of the hydraulic pump required by the hydraulic device.

In 50% of the fault diagnosis problems, basically the errors are the problems of power supply, air source and hydraulic source. For example, there are problems in power supply, including the failure of power supply in the whole workshop, such as low power supply, burned fuse, poor contact of power plug, etc; It is caused by the failure to open the air pump or hydraulic pump, the failure to open the pneumatic triplet or triplet, and the failure to open the load relief valve or some pressure valves in the hydraulic system. These basic problems are usually the most common ones.

Check whether the sensor position is offset

Due to the negligence of equipment maintenance personnel, there may be errors in the position of some sensors, such as not in place, sensor failure, sensitivity failure, etc. The sensing position and sensitivity of the sensor shall be checked frequently, and the deviation shall be adjusted in time. If the sensor is broken, it shall be replaced immediately. Many times, if the power supply, air source and hydraulic source are guaranteed to be correct, the more problem is the sensor failure. In particular, due to long-term use, the internal grounding may stick to each other and cannot be separated, resulting in normally closed signal, which is also a common problem of this type of sensor and can only be replaced. In addition, due to the vibration of the equipment, most sensors will be loose after long-term use. Therefore, during daily maintenance, it is necessary to often check whether the position of the sensor is correct and whether it is firmly fixed.

Check relay, flow control valve and pressure control valve

Like the magnetic induction sensor, the relay will also have grounding adhesion after long-term use, so the normal electrical circuit cannot be guaranteed and needs to be replaced. In the pneumatic or hydraulic system, the opening of the throttle valve and the pressure regulating spring of the pressure valve will also loosen or slide with the vibration of the equipment. Like sensors, these devices are components that need daily maintenance in the equipment. Therefore, in daily work, these devices must be carefully inspected.

Check the electrical, pneumatic and hydraulic circuit connections

If no problems are found in the above three steps, check all circuits. Check whether the wires in the circuit are open circuit, especially whether the wires in the trunking are cut by the trunking due to pulling. Check the air tube for damaging creases. Check whether the hydraulic oil pipe is blocked.

When checking the circuit in this step, use the necessary multimeter and adjust it to the buzzer gear to check the path of the circuit. If the air pipe has serious creases, replace it immediately. Replace the hydraulic oil pipe as well.

After ensuring that the above steps are correct, the fault may appear in the controller, but it can never be a program problem! The controller will not be damaged as long as there is no serious short circuit in the controller.

First, check whether the equipment with high-frequency interference is near the controller. If so, move it away immediately. If it is outdoors, high-intensity lightning may also cause the controller to fail to work normally in an instant. At this point, first clear all possible interference devices, and then restart the controller.

Secondly, if the restart is invalid, check whether the controller wiring is loose and has poor contact.

Finally, if the wiring is correct. Judge whether there is a problem with the memory card of PLC. Replace a new card, download the program, and check whether the previous memory card is faulty.