Analog and digital signals from the field are sent to the DCS system via safety barriers; how is the output handled? Does the analog output require a safety barrier? Open...
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Analog and digital signals are sent to the DCS system via safety barriers; how is output handled? Does the analog output require a safety barrier? How is digital signal output?
If the field instruments being used are intrinsically safe instruments, is a safety barrier still required?
Yes, intrinsically safe instruments in combination with safety barriers
Intrinsic safety instruments all need to be used in conjunction with safety barriers; there are corresponding safety barriers for both analog and digital signals, as well as for 485 communication – it depends on whether you need them or not
Intrinsic safety instruments must be used in conjunction with a safety barrier. Other ordinary signals do not require a safety barrier. Regarding how to output and input, it is a command using a 4–20 MA signal for control and feedback. It mainly depends on whether it’s input or output
It is advisable to add a safety barrier for analog output, while relays or isolation barriers are recommended for digital output