Issues regarding safety barriers for four-wire instruments
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Dear friends from Sichuan, I am working on a project currently, and foreign instruments have been selected for use – they are four-wire type and intrinsically safe. I would like to ask whether such safety barriers are available If possible, could you provide some information? I’ve consulted several manufacturers, and all of them can isolate the signals, but not the power supply. I’m torn
For 4-wire instruments passing through the safety barrier, it is the signal wires that go through the barrier; the two wires for power supply are simply ordinary 24VDC plus a fuse, and that’s sufficient. .
In that case, wouldn’t it no longer meet the intrinsically safe requirements?
The instrument power supply is provided separately, while the signal lines are connected to the safety barrier. The wiring method for the safety barrier differs from that of 2-wire instruments, and safety barriers from different manufacturers vary; simply follow the instructions for wiring
Just connect the wires according to the instructions; but in explosion-proof environments, it’s sufficient to seal those connection points with explosion-proof putty after wiring them up, hehe
For 4-wire systems, we generally choose explosion-proof types.
Our hydrogenation units here have quite strict requirements. In the past, we used two-wire intrinsically safe systems; now we need to keep compatibility with the previous systems, but the instruments are four-wire type, which is why this problem arises. I checked yesterday and found that some safety barriers are four-wire type, but they seem to lack power supply. Thank you all for your active participation in the discussion.