7 Loop Powered Signal Isolator Wiring Diagrams

Loop powered signal isolator is one type of signal isolator with a power supply module. The function of the loop powered signal isolator is to isolate the current source signal input to the loop powered isolator and output a DC signal that is isolated from and proportional to the input signal.

Loop powered signal isolators use the signal current in the input loop to power the meter (take out some energy of input signal inside the isolator to drive the isolator), without any external power supply.

Using an external powered signal isolator (such as the ATO-S-SINIR-210E) in the control system requires the installation of isolators and external power supply that support the operation of the isolator in the control cabinet of the control system. The use of loop powered signal isolators not only serves as signal isolation but also don't require an external power supply, which saves one-third of the wiring effort, and the cost of the power cable and the power supply.

The following is seven wiring diagrams of the loop powered signal isolator and the various powered sensors and the different types of control system input module (or input of instrument).

I. The wiring method of the external powered transmitter

1. Wiring diagram of loop powered isolator with external powered 4-wire transmitter:

Note: This is a typical wiring diagram of a loop powered signal isolator (get energy from the input) and 4-wire transmitter, detailed parameters of loop powered signal isolator (ATO-S-SINIR-502E) are in the product page.

2. Wiring diagram of loop powered isolator with external powered 3-wire transmitter:

3. Wiring diagram of loop powered isolator with external powered 2-wire transmitter:

II. The wiring method of the external powered input module/instrument

1. Wiring diagram of loop powered isolator with input signal of 4-wire transmitter:

2. Wiring diagram of loop powered isolator with input signal of 3-wire transmitter:

3. Wiring diagram of loop powered isolator with input signal of 2-wire transmitter:


Note: Since the power supply provided by the power distribution function of the control system input module (or input of instrument) is not isolated from the input terminal, the output signal of the power supply mode of the transmitter is common-grounded with power supply.

III. Wiring diagram of loop powered signal isolator with input signal of output module/instrument