Safety barrier issue
Thread Content
The explosion-proof instrument signals are displayed on the on-site digital display; the 4–20mA signal from this display is sent to the DCS. Is it still necessary to use a current isolation barrier at the detection terminal?
The flameproof type primarily relies on the equipment’s housing for flame protection; it has nothing to do with signals, and it can be included or omitted.
What is the function of a current isolation barrier?
It is recommended to add one; use an isolation barrier instead of a safety barrier, along with a protection card
When using flameproof instruments, a safety barrier or isolation barrier is not necessary. You can decide for yourself.
The safety barrier corresponds to intrinsically safe instruments; in the past, we encountered on-site solenoids that were explosion-proof and had high power, and the relay-based safety barrier was not capable of handling them
If the flameproof instrument is to be integrated into the SIS system, it is recommended not to add it, as this will create an additional point of failure and reduce the safety of the circuit; if it is to be integrated into the DCS, then it doesn’t matter and it can be added or not as desired