Hollysys PLC - the debugging steps of PLC

1. Check the circuit according to the drawing (without power transmission)

The drawings of the general PLC system include two parts: the drawings in the cabinet and the drawings outside the cabinet; The drawing in the cabinet refers to the wiring diagram inside the cabinet; The out-of-cabinet drawings are the wiring diagrams of all electrical cabinets that are connected out. This part needs to be checked for; 1. Whether the drawing design is reasonable, including the capacity of various components, etc. 2. Check whether the components are connected in strict accordance with the drawings according to the drawings.

In this process, the most important thing to pay attention to is to check the power supply,1 to make sure that there is no short circuit in the circuit. 2. Make sure that the strong and weak currents are not mixed together; Because the PLC power supply is 24V, once the 220V is connected to the PLC due to the wrong wiring, it is easy to burn the PLC or expansion module.

2. Check the external circuit of the PLC, which is commonly known as "dotting"

After the power supply is confirmed, the power is transmitted, and the input and output points are tested, which is commonly known as "dotting", and the test IO points need to be tested one by one, including the operation button, the emergency stop button, the operation indicator light, the cylinder and its limit switch, etc., the specific method is that one person operates the button on the field side, etc., and the other person measures and monitors the input and output signals in the PLC; For large systems, test sheets should be established, i.e., marked after testing. If it is found that there is a wiring error during the construction process, it needs to be dealt with immediately.

In this step, it should be noted that it is necessary to clear the program in the PLC or disable the program after backing up the program to avoid the operation of the equipment caused by the test.

3. Check the mechanical structure and test the motor load

This step needs to check whether the mechanical structure is tightened, etc., whether the motor load is properly protected to avoid accidents caused by accidents, and after the inspection is completed, it is necessary to manually test the operation of the equipment, such as forward and reverse motors, whether the circuit is intact and electrified, and the inverter class sets the corresponding parameters and optimizes the motor, static identification or dynamic identification, etc.

It should be noted here that for some special loads, such as those that move up and down vertically, they need to be carried out by professionals to avoid test accidents due to improper control.

4. Debugging manual mode/semi-automatic mode and related logical relationships

After testing both the IO point and the load side, the next step is to debug in manual mode. The manual mode here can also be called semi-automatic mode, which does not directly press the solenoid valve or contactor by hand, but refers to the drive of the device through the button or HMI button, etc., which corresponds to the automatic state. The manual mode of testing can decompose the automatic mode according to the person's wishes, which is convenient for the test procedure.

The most important thing in this process is to test the safety function, i.e. to test whether the safety functions such as emergency stop, safety light curtain, etc., play a corresponding role in the operation of the equipment.

5. Debug the automatic mode according to the production process

After the semi-automatic commissioning is completed, the automatic work can be further commissioned. This link is the most important, it is necessary to test various interlocks according to the production process, including logical interlocking, safety interlocking, etc., and to test several more working cycles to ensure that the system can work correctly and continuously.

6. Testing of special processes

In addition to logic control, there are many extended functions in the PLC system, such as PID control, etc., when these logic debugging is basically completed, you can start to debug analog and pulse control. The most important thing is to select the appropriate control parameters. Generally speaking, this process is relatively long. It is necessary to adjust patiently, and the parameters should also be selected in a variety of ways, and then the best one should be selected. For some PLCs, the PID parameters can be obtained by autotuning. However, this self-tuning process also takes a considerable amount of time to complete.

7. Complete all the above steps

The whole debugging is basically complete. The next step is the pre-production step, pre-production is the pre-production work test, in this stage can cooperate with the production to carry out some special tests, such as whether the production rhythm is satisfied, whether the safety function can still work under the load, etc., generally continuous production can be delivered after a certain period of time.

Hollysys PLC - the debugging steps of PLC

Hollysys PLC - the debugging steps of PLC

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