Transmission of DCS and field signals
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Experts, may I ask how analog signals from the field are transmitted to the DCS, and how DCS signals are sent to the field valve positioners? Thank you.
The signal is converted into a 4-20mA current and transmitted via cable
The signal from the field instruments is of type AI, while the signal from the valves is of type AO; both are 4–20 MA signals. The signal from the field instruments passes through a transmitter (for AI signals), is transmitted via signal cables to the junction box in the cabinet room, from there to the safety barrier, to the AI card, to the controller, to the AO card, back to the safety barrier, and finally to the valves.
Don’t overcomplicate it; at its core, it’s all about current and voltage. The levels and temperatures that can be seen on the DCS are displayed after corresponding modules convert these currents and voltages. The same principle applies to the operation of valves on site
Basic knowledge of instrument automation.
Looks like a beginner with instruments: lol