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guys, a user on a Danish forum posted a question about the sms122.

he just set his up, calibrated it to pH7.

now as soon as the pH came close the the set point, the controller freaks out and starts shutting the relay on and off really fast( like a machinegun, was his wording)

anyone know what might cause this?
 

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It may be behaving similar to my AM Pinpoint pH Controller, so here's a guess:

When my controller gets close to a set point (it has 2) it will buzz--clicking on and off really fast--for a couple-3 seconds. Then when the set point reading is stable in does its thing--Open or Close. The Pinpoints have .01 readout and the milwaukee's only have a .1 readout, but from the controller's perspective--it may read .01--who knows? There is quite a gap from say 6.0-6.1, so my guess is that its just registering the set point, then not, then yes again, etc until it settles on getting a full clear reading. Mine doesn't snap the solenoid on and off--just makes a buzzing sound that varies in frequency and length. This is what it sounds like from Your description.

The probe may be questionable. The milwaukee weak spot seems to be the probe. But since its brand new--I would guess not......

HTH
 

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this is a standard issue in designing controllers. It is due to noise in the system. Naja is correct with this problem, and it should only become evident in poorly designed electronics (preventing it is very easy, and the prevention is unlikely to fail). What you should try before returning/exchanging is replacing the batteries/power supply, plugging it in a different outlet, or recalibrating the probe. Finally, you could try replacing the probe, but a well designed controller should correct for a poor probe (ie, i would try a different brand of controller first).

Brandon

ps first post, long time lurker
 

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It's also worth shooting them an email and asking the tech people.

After 6 months of use, an issue came up with mine, and they were courteous & prompt. They responded to my email question the next day and asked me to send it in. I sent it in that day, and by the end of the week, I had a new unit. Entire transaction took one week. I was pretty amazed at their service.

-p
 

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Not to Hi-jack, but I purchased one of the Omega PHE-4202 probes and it should arrive Thursday. I'll repost and let everyone know if there is any change.

I think my AM Pinpoint Probe is at the end of its reliable life, so, as cbfreder mentioned, that may be one of the reasons for the buzzing that I hear ......
 

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Hello :)
Its me who has the problem with the controller. What I have done is to test the controller outside the tank from 7.6PH to 6.6PH in small steps using water from the tank, and slowly dripping acid (HCl) into it. It didnt become unstable at any point, ie. I could not recreate the incident.

One theory I have though is that as the membrane reactor I use is positioned somewhat below the probe, it is possible that CO2 gas, that escapes the reactor every now and then, have gotten up under the hood of the probe, and thereby yielded unstable measurements.

I have reconnected the controller to the tank, and I am keeping a steady eye on it for a while. I also sent the question to Milwaukee, and am awaiting an answer.

regards

Christian Hansen
 

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mine does the same thing too. i'm sending it in for replacement then selling the thing.i ordered a pin point ,hope i get better luck
 

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Hello! after many years if anyone knows about this problem it would be nice, i have the same problem and i know my probe is not good, if i change the probe it would be ok again the controller?
 
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