What does the ZT equation on the DCS screen in an ethylene plant mean?
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What does “ZT 26%” mean next to the valve in the DCS display? Is it the valve opening degree? On the mechanical display of the compressor, there are instruments marked with JI and *. What do these mean? What are their functions?
It seems to be a valve opening of 26%
Valve position feedback. . . . . . . . . .
It’s a ZT valve position transmitter; therefore, 26% refers to the degree of opening, so what everyone is saying is correct
The initial letter Z denotes the actuator, position; T stands for transmission, and ZT refers to the transmission of the actuator’s opening degree. J represents power, I denotes an indicator; JI is the indicator for compressor power. X is an arbitrary value with no definite definition; it would be helpful to have access to the construction drawings’ legend. It is recommended that the original poster refer to the following document when encountering similar issues: HG-T 20505-2000 Function Indicators and Graphic Symbols for Process Measurement and Control Instruments.pdf