[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[APD] Re: Milwaukee pH controller problem

My ph controller is having some recent issues. Whenever it trips (turns solenoid on) it seems to quickly "reset" the controller, which turns the solenoid off. When it settles back out, it turns the solenoid back on (flow position) and it happens again. It just started a day or two ago but I woke up to it ringing (back, forth, back, forth) since the solenoid itself isn't very quiet when closing.

Since no one else has answered this I'll give it a shot. I don't have one of these controllers but can offer some general advice that might help you solve this problem. First, try to keep the solenoid and it's associated cabling as far apart as possible from your pH sensor and it's cable. The large current spikes the inductive solenoid will generate at turn-on and turn-off may be coupling into your pH sensor and causing the controller to get false readings (and make bad control decisions as a result). Getting a ferrite bead from Radio Shack and winding the pH sensor cable around it a few times might also help as the ferrite will help to suppress electrical impulse noise in the sensor cable. No guarantees though :-)

I haven't cleaned the pH probe yet and it's older (1+ year), but it was working well at the last test (3 weeks ago). The other possible problems would be relay in the 120v plug for the controller is requiring too much power and turns the controller off when actuating the relay (but it's never done it before) and finally, some stray voltages are causing odd, instantaneous readings in the pH probe itself (grounding probe might help?).

If the relay is drawing enough power to cause the controller to shut down then something is very wrong with the relay. Check it to see if it is hot -- in normal operation it should be warm, but not painfully hot to the touch. You could try substituting a small light bulb (7-15 watt or so) for the solenoid and if the controller doesn't experience any problems when switching the light bulb on and off at least you know the problem is not with the controller itself.

You may also want to try plugging and unplugging all the connections to the controller (power and probe) a few times. This should help to clean off any minor corrosion in the connectors that might be causing problems.


***************************** Waveform Technology UNIX Systems Administrator

Aquatic-Plants mailing list
Aquatic-Plants at actwin_com