There are more types of analog input input isolators, which are divided into single and double channels from the number of input safety channels, and the types of data signal dispatch functions of one input and two output channels. Power supply methods are divided into: loop power supply type and separate power supply type. Signal input isolator.

Circuit power supply type signal isolator alias microwave sensor signal isolator, its input and output are two-wire, wiring is very convenient, it DCS, PLC or display information table to provide power through the protection to the two-wire transmitter distribution equipment, in addition, the two-wire transmitter caused by 4-50mA data signal protection input to DCS, PLC or display information table. It is ideal for on-the-spot, two-wire transmitters that need to be protected from input to DCS, PLC systems or digital meters, and the input card of the input machine equipment has an internal power supply function. Signal input isolator.

However, the microwave sensor signal isolator has shortcomings:

1, the microwave sensor signal isolator is equivalent to a load, after the isolator in the middle of the protection of both sides of the pressure drop does not exceed 6V, so it to the two-wire transmitter distribution equipment working standard voltage will be reduced, the general provisions of the transmitter 12V power supply can work.

Example: Power supply 24V, RL=250Ω, when 50mA, to provide the two-wire transmitter distribution equipment working voltage UO≈24V-0.02×RL-6≥13V, so the general provisions of the two-wire transmitter to 12V working voltage all normal operation.

2, microwave sensor signal isolator transmission precision relative to the isolation of a separate power supply is a little, 0.4% F.S., need to pay attention to when using.

Individually powered type

It is the more common signal isolator XP series product with a two-wire transmitter, which must be powered separately to the isolator. Its characteristics are:

1, signal isolator transmission accuracy, achieve 0.1% F.S.

2, signal isolator XP series products wiring method is convenient, can be connected to two-wire transmitter, four-wire transmitter or current source data signal, easy and convenient application.

3, switching power supply, input, output intermediate complete protection, to ensure high anti-interference ability. Signal input isolator.