Seeking help with a question regarding the PID legend in chemical engineering
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There is a symbol in the chemical process PID diagram whose meaning I’m not sure about: it’s a circle with a horizontal line in the middle, “EU” written above it and a tag number written below. What does “EU” mean? It’s next to the motor; I guess it’s a motor status signal, or related to the motor’s start/stop operation. Seeking help from experts to answer this
Check the first page of the set of drawings you have
There is now an EU meter: I’m not sure if it is indicated in the PID diagram – the output current display
E represents voltage (electromotive force), while U represents multi-functionality； The EU specifies multiple requirements for the reading of the voltage (electromotive force) of the motor; these reading requirements may include functions such as indication, recording, and alarm lighting. The specific reading functions are detailed in the design documents.
Check the legend description on the first page of the set of drawings you have.
EU12**** denotes the address of the motor; to find out whether there are any other functional status indications, it is necessary to consult the instrument index table.
Typically, a proper PID diagram includes explanations of the symbols on its first few pages
EU motor start/stop status signal.
EU = excitation unit; it’s an excitation unit. I’d ask those in charge of electrical maintenance – that’s what it should be.