SFA-1□□4 isolated safety barrier is a type of DDZ-S instrument. In normal state, the safety barrier does not affect the normal operation of the system. When there is fault, the safety barrier will limit voltage and current and restrict electric energy within limits to ensure safety. It is widely used in petroleum, chemical industry, light industry and other inflammable and explosive places. It has the following characteristics:

Detected terminal barrier is used with two-wire transmitter and supply power for it. It can restrict dangerous energy enter into dangerous place. Isolated safety barrier can convert 4～20mADC signal from transmitter to isolated 4～20mADC signal output and some models support HART communication.

The operated terminal safety barrier is used with actuator. It is not only restricting dangerous energy enter into dangerous place but also isolating signal.

To compare with zener safety barrier, isolated safety barrier is more complex on structure but it has the function of isolating signal so it is easier to be accepted by user.