Analog issues with generator power

Doing an installation with generator power and analog is very strange.
Calibrated 6 of 7 pH meters, 7th wouldn't zero, went back to the others and they wouldn't zero. Also have 4-20 ma pressure sensors and 1 works, 1 doesn't.
No ground?
Something in sin wave from generator?
Noise?
??

Since your analog sensors operate off DC (even the pH output is DC) it is unlikely that the generator power waveform itself is the problem. Check grounding on the generator, and make sure you are using shielded cable for all your transmitter signals, ground the shield at one end only, and do NOT run the analog signals in the same conduit with AC and DO NOT use wire nuts on any analog signal connections.

Most genset problems can be traced back to grounding issues. Gensets and variable frequency drives are the worst offenders to the analog community for causing problems.

1) For vfd's always ground the motor back to a proper ground bus, never to the vfd case.

2) Keep everything away from the incoming and outgoing wires.

3) Shield all DC and analog wiring and ground the shield at one point only!

4) Make sure that the grounds are adequately sized!

I am sure that there are other things to check, but this is a start.

Generator was not properly grounded. Grounding fixed it. Thanks for all your help.

I've had a few problems on my transmitters using WAGO terminal blocks (wire held in by spring action), wire will somehow come off, I've been replacing them with Weidmuller connectors.