From memory, PCB ICP load cells (that's IEPE by another name) have a typical bias voltage of around 10 V, which is usually stripped by a capacitor on the excitation amplifier (or the 9234 in this case). I used to have a series of triaxial load cells that were biased to 10.25 V.
PCB sell a number of relatively inexpensive external amplifiers themselves, but take care to mention to their sales representative that your interest lies in static or quasi-static measurements. I bought a 482C05 four channel amp and decided to use it for low-rate tests, and found that the decay was considerable in one set of tests thanks to the amplifier time constant. One cheap and cheerful solution was to connect a BNC T-piece at the amplifier/load cell connector and branch off the signal. This is where the bias voltage is important - I was fortunate to have a 16 bit DAQ with which I could just about measure signals using the 10 V range - as you would need to remove the DC offset somehow to read with a 5 V DAQ. I was planning on using a nice steady voltage regulator opposing the load cell until I found my DAQ was capable of handling the measurement. On the plus side, DC performance was now no longer affected by the amplifier's frequency response 🙂
So, tl;dr - get another excitation source and remove the DC offset voltage if you want to measure in DC coupling.
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CLA
