Is it possible in circuit design to split like say a temperature sensor line reading into 2 wires, and read by 2 different system/circuitry? My motive is to tap the signal line in a safe way without affecting or disrupting the other system functioning.


It depends of your sensor.


  • If it's an RTD, then no, because the circuit needs to drive a current through the RTD and measure the voltage across the resistor, if you have 2 circuit, current will add-up and the voltage won't match expectation.
  • If it's a voltage based sensor, like a thermocouple, it should be fine as long as there isn't some active compensation or active signal filtering.
  • If it's a current based sensor, then you would have to add some circuitry.

Digital: If its a 2 wire communication digital sensor, then you can have an active master to read out the sensor and you can passively "tap" the wire to catch the readout.

You can provide more detail about your sensor (like a reference, datasheet).

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  • \$\begingroup\$ Thanks for your info. The sensor is actually a thermocouple wired to PLC. I planning to have a microcontroller to read the temperature reading by tapping the line. So I was wondering is there like a splitter/extra circuit which will maintain the quality of the signal all the time. The extra circuit I chanced upon internet was isolation amplifier, haven't actually explore yet. By the way, what is current based sensor on your third point? I searched google couldn't find any info on that. \$\endgroup\$ – sunny Jan 4 '19 at 3:04
  • \$\begingroup\$ I suspect Damien is alluding to the standard 4-20 mA current loop interface ( en.wikipedia.org/wiki/Current_loop ). \$\endgroup\$ – davidcary Jul 29 '19 at 1:25

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