The use of signal isolation methods in the various process loops can be achieved by isolating cards such as DCS or PLC or field transmitters with isolation (some devices can do it), or by using signal isolators. In comparison, the use of signal isolators has the following advantages:

● In most cases, the use of signal isolators + non-isolated cards is cheaper than the use of isolated cards.

● The signal isolator is better than the isolation card in terms of isolation ability and electromagnetic interference resistance.

● The signal isolator is flexible in application, and it has model conversion and signal distribution functions, which is more convenient to use.

● The signal isolator usually has single channel, double channel, one in two out and other channel forms, and the channels are completely independent from each other, which makes the configuration and daily maintenance of the system more convenient.