Hysteresis mode short cycling a freezer

[brahn]

You can try changing the PID settings to what they are in the first line, but none of them after Output Heat/Cool are used in Hysteresis mode. It wouldn't hurt as a troubleshooting step just to see if somehow that makes a difference.

If there's nothing else running at the time and no ladder logic, I don't see how you're getting this behavior. Can you try putting this into a process instead of using Manual Mode to see if that might make a difference?

[RDH_Texas]

I created a process with one state, to control to 30F with a 4 degree band. When the temp drops below 34 the system shuts off. No changes...

What else can I try?
Is there a way to dump any memory, or download the firmware image?

[brahn]

You could send me the config files, but I don't have a way to hook it up to a freezer/chiller to test it. I could take a look at the other settings and see if there's anything going on that looks out of the ordinary. You could try upgrading to 3.7.1 to see if that will fix it. We didn't specifically change anything related to this, but then again we haven't heard of anyone else having this problem either.

[RDH_Texas]

I've upgraded my BCS 460 to 3.7.1 and then to the 4.0 Beta 3.
I still get problems with the hysteresis I mentioned below. It happens in cool and heat mode. I used it in heating mode to run a RIMS heater, and noted that at the 150F set point it would turn on when the temperature dropped below, and off when it went up above, instead of turning off below the hysteresis deadband (1 degree in this case)

Has anyone else run into this problem? I think I have the temperature probes grounded properly, but for some reason the system isn't working how I expect.

Any help would be appreciated.
Thanks,
Bob

[JonW]

I used it in heating mode to run a RIMS heater, and noted that at the 150F set point it would turn on when the temperature dropped below, and off when it went up above, instead of turning off below the hysteresis deadband (1 degree in this case)

Bob, I'm not 100% clear on what you're saying here. You say that it turns on when it drops below 150 - which it is supposed to. It will turn heat on at 149 if your swing is 1 degree and then back off at the set temperature of 150.

[RDH_Texas]

What I am saying happens is that with a 1 degree deadband, the heater turns on at 149.9 and off at 150, when it should turn on at 149.0