toddp65
Member
We installed a pH control system in our wastewater system.
pH probe report to a Rosemont analyzer and send a 4-20 signal to our controller and then to Ignition SCADA.
One of the tanks (Tank 2)has the pH maxed at 22 mA and the first tank with the same wastewater is functioning correctly. When the agitator motors are turned off (They are driven by PF 525s) The pH returns to normal. This only occurs in tank #2. The probe and analyzer has been verified. Bonding and grounding of motors and drives and conduit verified as well. When you place the suspect probe in tank 1 with the drives running, it reads normally. Take it to tank 2, drop it in and it maxes out immediately. Again, turning off the agitators on both vessels the probe reads normal until you enable either or both motors and then it's maxed out.
This probe is brand new and acts exactly as the first one installed.
I suspect it's an issue with the VFDs and have recommended noise filters on the terminal/load side of the drives. Does this make sense?
Thanks
pH probe report to a Rosemont analyzer and send a 4-20 signal to our controller and then to Ignition SCADA.
One of the tanks (Tank 2)has the pH maxed at 22 mA and the first tank with the same wastewater is functioning correctly. When the agitator motors are turned off (They are driven by PF 525s) The pH returns to normal. This only occurs in tank #2. The probe and analyzer has been verified. Bonding and grounding of motors and drives and conduit verified as well. When you place the suspect probe in tank 1 with the drives running, it reads normally. Take it to tank 2, drop it in and it maxes out immediately. Again, turning off the agitators on both vessels the probe reads normal until you enable either or both motors and then it's maxed out.
This probe is brand new and acts exactly as the first one installed.
I suspect it's an issue with the VFDs and have recommended noise filters on the terminal/load side of the drives. Does this make sense?
Thanks