Separation of analog signals

The essence of the use of signal isolators is galvanic separations of two systems: an electronic device (eg. PLC or IPC) from the device often located in the area and therefore exposed to the harmful influence of other factors: people, lightnings etc.

Additionally, in the case of analog signal, there may be carried out conversion from one standard to another one.


Protection of the PLC’s analog output and conversion output signal of 0-10V to 4-20mA for inverter driving.



The necessary elements for the implementation of the system:

  • U1: universal analog isolator LXA-U1U,
  • V1: inverter,
  • 24V DC power supply.


1. Connect the circuit shown in the scheme.
2. Set the switches on the front of LXA-U1U:

  • Input: 0-10V,
  • Output: 4-20mA.


  • Protection of the controller’s outputs from damage,
  • In case of failure, replace the separator only, not the whole I/O card (in which there can be broken only one input/output)
  • Conversion of the output signal to another one required by the user,
  • Using universal isolators allows the user to independent change input and output signal range on his/her own.
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