IMany beginners in electrical engineering may not know how to start debugging after completing the design process of electrical control cabinets and PLC programs, or some may encounter issues such as PLC burning due to improper debugging methods. So, how should the designed electrical system be debugged? You can follow the following seven steps.

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

The drawings of a general PLC system include two parts: inside cabinet drawings and outside cabinet drawings; Cabinet drawings refer to the wiring diagrams inside the cabinet; The drawings outside the cabinet are the wiring diagrams for all electrical cabinets that are connected out. What needs to be checked in this section is; 1. Is the drawing design reasonable, including the capacity of various components, etc. 2. Check whether the components are connected strictly according to the drawing.

The most important thing to pay attention to during this process is to check the power supply and ensure that the circuit is not short circuited. 2. Ensure that strong and weak currents are not mixed together; Because the PLC power supply is 24V, once 220V is connected to the PLC due to wiring errors, it is easy to burn the PLC or expansion module.

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

After confirming the power supply, power on and test the input and output points, commonly known as "dotting". Testing the IO points requires testing one by one, including operation buttons, emergency stop buttons, operation indicator lights, cylinders and their limit switches, etc. The specific method is to have one person operate the buttons on the site side and the other person monitor the input and output signals on the PLC; For large systems, a test table should be established, that is, marked after testing. If any wiring errors are found during the construction process, they need to be dealt with immediately.

In this step, it should be noted that it is necessary to back up the program and clear the program in the PLC or disable the program to avoid device actions caused by testing.

3. Check the mechanical structure and test the motor load

This step requires checking whether the mechanical structure is tight, and whether the motor load is properly protected to avoid accidents caused by accidents. After the inspection is completed, it is necessary to manually test the operation of the equipment. For example, for forward and reverse rotation motors, it is necessary to test the integrity of the circuit and conduct live testing. For frequency converters, corresponding parameters should be set and motor optimization, static identification or dynamic identification should be carried out.

It should be noted here that for some special loads, such as vertically moving loads, they need to be carried out by professional personnel to avoid testing accidents caused by improper control.

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

After testing both the IO point and 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 driving the device through buttons or HMI buttons, which corresponds to the automatic state. Manual mode testing can decompose the automatic mode according to human preferences, making it easier to test the program.

The most important thing in this link is to test the safety function, that is, to test whether the emergency stop, Light curtain and other safety functions play a corresponding role in the running state of the equipment.

5. Debugging automatic mode according to production process

After completing semi-automatic debugging, the automatic work can be further debugged. This link is the most important and requires testing various interlocks according to the production process, including logical interlocks, safety interlocks, etc., and testing several more work cycles to ensure that the system can work continuously and correctly.

6. Testing of special processes

In addition to logic control, there are many expanded functions in the PLC system, such as PID control. After these logic debugging are basically completed, you can start debugging analog and pulse control. The most important thing is to select appropriate control parameters. Generally speaking, this process is relatively long. Be patient and make multiple choices of parameters before selecting the best one. Some PLC, its PID parameters can be obtained through Self-tuning. But this Self-tuning process also needs considerable time to complete.

Spot Products