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Alex

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Reply with quote  #16 
No John, there IS a real problem, just too hard to explain briefly. Maybe I will talk about it later when I have time, but it's not the point of my question. I think in this case the question can be answered without those details.

Meanwhile I studied a solution with external devider module with its own power (I think that was Oli's idea), capable of fine signal tuning but unfortunately you can't turn the power off in the instrument nor software. Well you can, but you spend warranty.
OLi

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Reply with quote  #17 
isolate adjuster from meas box by AC coupling with a capacitor or will you get sensor fail then?


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Walt Strong

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Reply with quote  #18 
If the "box" provides ICP (IEPE) power to both accelerometers at same time and the switch connects the accelerometer one at a time to analyzer, then an AC-coupled voltage divider or transformer could attenuate the highest signal. If the accelerometers are 2-wire and the "box" only contains a switch that connects both signal and ICP power from analyzer, then voltage divider or transformer would also reduce ICP voltage (DC), and perhaps not work at all. Perhaps a discussion with an electronics wiz would off better advice! Be aware that attenuation may not be uniform at high frequencies.

Voltage Divider Rule with Examples

From <https://www.elprocus.com/voltage-divider-rule-with-examples/>

Walt

OLi

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Reply with quote  #19 
Since IEPE is constant current supply system it is not so easy to predict what a basic divider do it may not influence the supply to the sensor since it may accept 2-12 mA w/o interference but having the supply separate from the divider is the "easiest" if the signal may be sent back to the system ib some way.
If the system is to be verified why don't connect 2 sensor simulators trimmed to be identical at a suitable level?

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Alex

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Reply with quote  #20 
Thank you all for your answers, I think I can build on this what you have written.
Mahyar

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Reply with quote  #21 
I think you have to provide an RC (Resistor Capacitor) filter in a low pass manner to reduce some high frequency content of accelerometer (A) to get it near (B). You can perform the calculations from a white paper from IMI company about how to calculate the filters for long cable accelerometers.
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