Power supply, including the power supply of each equipment and the power supply of the workshop, that is, all the power supply that the equipment can involve.

Air source, including air source required by pneumatic device.

The operation of hydraulic sources, including hydraulic pumps required for hydraulic installations.

In 50% of the fault diagnosis problems, basically the error is the power source, the air source and the hydraulic source problem. Such as power supply problems, including the whole workshop power failure, such as low power, insurance burned out, poor contact of the power plug; The air pump or hydraulic pump is not opened, the pneumatic triplex or the two couplets are not opened, the pressure relief valve in the hydraulic system or some pressure valves are not opened, etc. These basic questions are often the most general.

Check sensor position for offset

Due to the negligence of equipment maintenance personnel, there may be some errors in the position of sensors, such as not in place, sensor failure, sensitivity failure and so on. Always check the sensor's sensing position and sensitivity, and adjust the deviation in time. If the sensor is broken, replace it immediately. In many cases, if the supply of power, air and hydraulic power supply is correct, more problems are caused by sensor failure. Especially the magnetic induction type sensor, because of long-term use, it is likely to be internal tie iron mutually stuck, can not be separated, the occurrence of normally closed signal, which is also a common problem of this type of sensor, can only be replaced. In addition, due to the vibration of the equipment, most of the sensors will be loose in position after long-term use. Therefore, it is necessary to check whether the position of the sensor is correct and fixed firmly during daily maintenance.

Check relay, flow control valve, pressure control valve

Like the magnetic induction type sensor, the relay can also be used for a long time to cause adhesion of the lapping iron, so the normal electrical circuit cannot be guaranteed, and it needs to be replaced. In pneumatic or hydraulic systems, the throttle valve opening and pressure regulating spring of the pressure valve can also come loose or slide with the vibration of the equipment. These devices, like sensors, are part of the equipment for routine maintenance. So in daily work, these devices must be carefully checked

Check electrical, pneumatic and hydraulic circuit connections

If no problems are found in the three steps above, check all loops. Check if the wire in the circuit is broken, especially if the wire in the wire groove is cut by the wire groove due to pulling. Check the air tube for damaging creases. Check hydraulic tubing for blockage.

In this step to check the circuit, use the necessary multimeter, set the buzzer to check the circuit access. If the windpipe creases badly, replace it immediately. Hydraulic tubing also needs to be replaced.

Failure may occur in the controller only after the above steps are guaranteed to be correct, but it can never be a program problem! First of all, do not destroy the controller, as long as there is no serious short circuit, the controller internal short-circuit protection, general short circuit will not burn the controller.

First, check if there is any high-frequency interference near the controller. If so, remove it immediately. If outdoors, heavy lightning can also cause the controller to fail in a flash. At this point, clear all possible interfering devices and restart the controller.

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

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