Check all power sources, air sources, hydraulic power sources, including the power supply of each piece of equipment and the power of the workshop, that is, all the power sources that the equipment can involve.
Air source, including the air pressure source required by the pneumatic device.
Hydraulic source, including the working conditions of the hydraulic pump required by the hydraulic device.
In 50% of the fault diagnosis problems, errors are basically caused by power, air and hydraulic pressure. For example, there is a problem with power supply, including the failure of power supply in the entire workshop, such as low power supply, burned out fuses, poor contact of the power plug, etc .; the air or hydraulic pump is not turned on, the pneumatic triple or two is not turned on, and the relief valve in the hydraulic system Or some pressure valves are not open. These basic questions are usually the most common ones.
Check whether the sensor position is shifted. Due to the negligence of equipment maintenance personnel, some sensor positions may be wrong, such as not in place, sensor failure, sensitivity failure, etc. Always check the sensor's sensing position and sensitivity, and adjust in time if there is a deviation. If the sensor is broken, replace it immediately. Many times, if the power supply, air supply and hydraulic supply are guaranteed to be correct, the more problem is the failure of the sensor. Especially for the magnetic induction sensor, due to long-term use, it is likely that the internal ground is stuck to each other and cannot be separated, and a normally closed signal appears. This is also a common problem of this type of sensor and can only be replaced. In addition, due to the vibration of the device, most of the sensors will become loose after long-term use. Therefore, during routine maintenance, you should always check whether the position of the sensor is correct and whether it is firmly fixed.
Check relays, flow control valves, pressure control valves. Relays, like magnetic induction sensors, can also be subject to ground adhesion for long-term use, which can not guarantee the normal electrical circuit and requires replacement. In pneumatic or hydraulic systems, the opening degree of the throttle valve and the pressure adjustment spring of the pressure valve may also loosen or slide with the vibration of the equipment. These devices, like sensors, are parts of the equipment that require routine maintenance. Therefore, in daily work, these devices must be carefully checked.
Check electrical, pneumatic, and hydraulic circuit connections. If none of the above three steps are found, check all circuits. Check whether the wires in the circuit are broken, especially if the wires in the trunk are cut off by the trunk due to pulling. Inspect the trachea for damaging creases. Check if the hydraulic oil pipe is blocked.
When checking the circuit at this step, use the necessary multimeter, set it to the buzzer, and check the circuit path. If the trachea is severely creased, replace it immediately. The hydraulic tubing must be replaced 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! First of all, don't be certain that the controller is damaged. As long as no serious short circuit has occurred, the controller has short circuit protection inside. The general short circuit will not burn the controller.
First, check if the equipment with high frequency interference is near the controller. If so, remove it immediately. If you are outdoors, high-intensity lightning may also cause the controller to malfunction. In this case, remove all possible interfering devices before restarting the controller.
Secondly, if the restart is invalid, check the controller wiring for looseness and poor contact.
Finally, if the wiring is correct. Determine if there is a problem with the PLC's memory card. Replace with a new card, download the program, and check if the previous memory card is faulty.