Wasn’t sure what category to select as the root of my issue is currently undetermined.
I have a groov Epic that is getting pH readings from 5 dual channel pH/ORP modules via and EB2.
The groov system has been installed to replace a bunch of individual Jenco 3671 analog units.
I’ve been troubleshooting a long list of independent issues and now have the groov system running fairly well with he exception of the pH readings. I am consistently getting readings from the groov unit that differs by 0.1 to 0.3 from the analog system. We are quite confident that the analog system is giving us the more accurate reading as our process fluid is seawater that has a nominal pH of 8.0 to 8.2 in our locale. The pH of the process fluid as measured by the groov system ranges from 7.7 to 7.9.
On the program side of things I use a simple interpolation-like equation that compares the raw analog output from the pH modules at buffers of 7.0 and 10.0 and the raw process actual reading and compare that with the ideal range to spit out an adjusted pH reading. It’s a standard 2-point calibration technique.
Without going into all the details of what I’ve done to attempt a solution to the slightly off readings I’m looking for some input from anyone with pH measuring experience on what they’ve done, things I should look at to resolve the accuracy issue I appear to have.