What is associative linkage?
Thread Content
The PLC in our company is **custom-designed**, and many of the interlocks are not documented; we have to figure them out gradually during production. However, the company’s management wants me to write down these interlocks, but I don’t know what they are. Guys, please help me out
Simply put: what action is triggered when the measurement value at a certain point exceeds the set value, as well as things like electrical interlocks. It would be better if the poster could share the program
The so-called associated interlocking refers to the causal relationship between input and output
In cases where such internal logical relationships are unclear, logical analysis should be conducted based on the known causal relationships. Express the internal logical relationships; such internal logical relationships are known as interlocking connections.
For example, the control object is: the ignition of the burner. The interlock condition is ； The combustion fan and exhaust fan have been started; the gas pressure is normal, and the boiler pressure and water level are also normal. The associated objects are: combustion fans, exhaust fans, and gas pressure. So what is the associated interlock object?
Actually, this is a basic conceptual issue. Talk more with colleagues in the chemical engineering field. If the gas pressure is considered to be PT-101, then there is a pressure interlock value of PSLL-101. If the pressure falls below PSLL-101, an interlock action is triggered. The device that can be involved in this interlock could be a solenoid valve, such as PSV-101; of course, it could also be an upstream DO output card.
Interlock issues cannot be taken lightly; regardless of who designed the system, interlock design diagrams must be provided. If you can’t even understand what the interlocks in the system are and how they function, then how can you operate and maintain it?