Electronic – Sensor question for low freq

signal integrity

A floating DC voltage output sensor will be powered locally and the signal will be sent outdoors 200 meters far away to a data acquisition board. I didn't receive the sensor yet and don't have the datasheet. But my question will be about something else.

For such long transmission I was first thinking to use a differential line driver at the sensor output or convert the voltage signal to current and send it as current or send as digital ect ect.

But I can use a differential ended input data-acquisition board has the following architecture:

Omitting the voltage divider effect, if I use this module and data acquisition as in below diagram would that be a adequate to eliminate common mode noise issues or capacitive coupling noise issues?Or still a differential line driver or current conversion is needed?

to be updated soon…

Best Answer

Because I have built so many remote sensors I used a SSM2142 600 ohm Diff line driver, but it needs +/- 15 volts to drive a 1K diff load 200 meters away. It needs +/- 18 volts to drive a distant 600 ohm load. Not needed here.


simulate this circuit – Schematic created using CircuitLab

I used 600 ohm STP cable with 22 awg wire as a twisted pair. Gives excellent AC (to 50 KHZ) and DC performance. You may need an op-amp to drive the SSM2142 as it does not have offset and gain trim built in, and its input impedance is only 10 K ohm.

In the schematic the 1K load divides the signal by 2, so the +/- 10 volt drive signal becomes +/- 5 volts at the isolation modules.

I am assuming you have DC power options at the sensor, but you have not clarified that.

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