Mypin pid controller problem

[TennBrewer]

Recently, my Mypin PID controller starts up cold ok, then after a minute or so it shuts off and restarts continuously. It behaves this way until I let it "cool down" for several minutes. I have had this working successfully for quite sometime until I tried to use it for controlling my electric smoker. I had to change the upper limit alarm setting but that was about all I changed. Did I fry it? Anybody have this experience or an answer?

 

[TennBrewer]

I got a replacement controller, similar model but not exactly the same. I wired it up and set the parameters identical to the malfunctioning one. It worked for a couple of minutes then started to reset itself, shutting off then back up from the start. Hmmm. I changed the control cycle time (Ctl) from the SSR setting (1 second) to the Relay setting (20 seconds). So far, it seems to be working fine now continuing to operate normally well past the point where it used to fail. One thing that puzzles me, though, is the setting for the relay. I have installed what I think is a Solid State Relay (SSR) but the recommended control cycle time setting for that makes it fail. I guess a longer cycle time isn't going to hurt anything.

 

[mattd2]

I got a replacement controller, similar model but not exactly the same. I wired it up and set the parameters identical to the malfunctioning one. It worked for a couple of minutes then started to reset itself, shutting off then back up from the start. Hmmm. I changed the control cycle time (Ctl) from the SSR setting (1 second) to the Relay setting (20 seconds). So far, it seems to be working fine now continuing to operate normally well past the point where it used to fail. One thing that puzzles me, though, is the setting for the relay. I have installed what I think is a Solid State Relay (SSR) but the recommended control cycle time setting for that makes it fail. I guess a longer cycle time isn't going to hurt anything.

Can you post details of the SSR you have? Possibly sounds like too much current draw and the PID has a current limiting thermistor to shut down to protect it.
And also a rough circuit diagram so we know how you have wired everything up?
If you only have power and the probe hooked up to the PID does it still cycle on/off?

 

[TennBrewer]

I think you're right, mattd2, the SSR may very well be the culprit. I was using a MYPIN SSR and ran it the Ctl parameter set to 1. The manual mentions that a shorter cycle time will wear out the relay. The thermistor sounds like it is causing the cycling so I have replaced the relay and setting the Ctl parameter to 15, or maybe 20. Thanks for your input, I am currently testing with the new relay now and will see how long it lasts. Good tip about troubleshooting without the relay connected, will try that if it happens again. Cheers.

 

[angrybits]

Short cycle time does not hurt SSRs. (It will wreck a mechanical relay.) If your pid controller is cycling on and off then you've got bigger problems. A diagram would help us help you better.