Another salinity probe Calibration Question

[PeterBel]

I have 3 x PM2 Modules, 2 are working no problem, 1 is giving me problem.

It seems that the 3rd PM2 module give me half of the value it should. I do the calibration process with a Calibration solution and do not use temp compensation.

After calibration, this module give me a value of 17 to 18 PPT. If you double that value, 34-36ppt seems right on target!

I tried with 2 other Salinity probes that are working with the other PM2 modules. I know that the Probes and calibration solution are working/good as i used them with the 2 other PM2 modules.

The only difference i can see between the modules, is the value of the offset. The working modules offset is somewhere between 30-40 while the non working module is at -579 which seems odd to me.

I tried to delete the module and re-install, update the firmware, disconnect and reconnect without success. Is there a setting somewhere that could divide the value by 2? or the module is bad?

Thanks for the help.

[rkpetersen]

If you have a Display module, there's a way to perform a true manual calibration on each of the probes. It's pretty easy to screw up your calibration if you're not careful with this, and I wouldn't recommend it for any probe that can be properly calibrated through the dashboard, but since that probe/module isn't functional right now anyway, it might be worth a shot.