1. Check all power, air, and hydraulic sources.
The power supply includes the power supply of each equipment and the power supply of the workshop, that is, all the power sources that the equipment can involve.
Air source, including air pressure source required by pneumatic device.
The hydraulic source, including the working condition of the hydraulic pump required by the hydraulic device.
In 50% of the fault diagnosis problems, the errors are basically the power supply, air supply and hydraulic supply problems. For example, power supply problems, including power supply failures in the entire workshop, such as low power supply, burned insurance, poor contact of power plugs, etc.; air pump or hydraulic pump is not turned on, pneumatic triple or double parts are not turned on, and the relief valve in the hydraulic system Or some pressure valves are not opened, etc. These kinds of most basic problems are usually the most common problems. 2. Check whether the sensor position has shifted.
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. Always check the sensing position and sensitivity of the sensor, adjust it in time if there is a deviation, if the sensor is broken, replace it immediately. In many cases, if the supply of power, air and hydraulic pressure is ensured, the more problem is the failure of the sensor. Especially for magnetic induction sensors, due to long-term use, it is likely that the internal ground irons will stick to each other and cannot be separated, resulting in a normally closed signal. This 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 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.
3. Check relay, flow control valve, pressure control valve
Relays are the same as magnetic induction sensors, they will also have iron adhesion after long-term use, so that the electrical circuit cannot be guaranteed and needs to be replaced. In a pneumatic or hydraulic system, the opening degree of the throttle valve and the pressure regulating spring of the pressure valve will also loosen or slip with the vibration of the equipment. These devices, like sensors, are parts of equipment that require routine maintenance. Therefore, in daily work, these devices must be carefully checked.
4. Check electrical, pneumatic and hydraulic circuit connections
If no problems are found in the above three steps, then check all circuits. Check whether the wires in the circuit are disconnected, especially whether the wires in the wire groove are cut by the wire groove due to pulling. Check the trachea for damaged creases. Check if the hydraulic oil pipe is blocked.
When checking the circuit in this step, use the necessary multimeter, adjust to the buzzer file, and check the path of the circuit. If the trachea is severely creases, replace it immediately. The hydraulic tubing should also be replaced.
5. 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 sure that the controller is destroyed. As long as there is no serious short circuit, the controller has short-circuit protection inside. A general short circuit will not burn the controller.
First, check whether there are high-frequency interference devices near the controller. If so, remove it immediately. If you are outdoors, strong lightning may also cause the controller to fail to work normally for a moment. At this point, first remove all possible interfering devices, and then restart the controller.
Secondly, if restarting is invalid, check whether the controller wiring is loose or has poor contact.
Finally, if the wiring is correct. Determine whether the memory card of the PLC has a problem. Replace with a new card, download the program, and check whether the previous memory card is faulty.