Hi everyone,
I'm wondering if there's anything left to try to get this PID to work properly. I've autotuned many times, played with some of the values, and even autotuned with a mash tun full of grain to fully simulate the actual use of my system. I'm using a RIMS tube to recirculate to a square cooler I mash in. I make ten gallon batches.
After transfering the strike water to the cooler, I recirculate and dial in the PID. I usually wind up a few degrees lower than the mash temp and try to use the PID to bring temps up without overshooting. Typically, the PID overshoots several degrees. In fact, when it hits the set temperature, it doesn't seem to change what it is doing, but keeps firing at about the same pace it had been firing at when raising the temp.
Now, if I turn the PID off right when it gets to the set temp, then turn it back on, it holds the temperature perfectly. But if I just let it ride it will overshoot.
Another odd thing is that when I autotune it the PID seems to work fine right afterwards. If I try and raise the temp after autotuning to a higher set temperature without first turning the PID off, it doesn't overshoot. But when I come back on brew day and use it to hit my mash temp, it overshoots.
Any thoughts? I'm ready to throw this thing out the window.
Cheers.
Dan
I'm wondering if there's anything left to try to get this PID to work properly. I've autotuned many times, played with some of the values, and even autotuned with a mash tun full of grain to fully simulate the actual use of my system. I'm using a RIMS tube to recirculate to a square cooler I mash in. I make ten gallon batches.
After transfering the strike water to the cooler, I recirculate and dial in the PID. I usually wind up a few degrees lower than the mash temp and try to use the PID to bring temps up without overshooting. Typically, the PID overshoots several degrees. In fact, when it hits the set temperature, it doesn't seem to change what it is doing, but keeps firing at about the same pace it had been firing at when raising the temp.
Now, if I turn the PID off right when it gets to the set temp, then turn it back on, it holds the temperature perfectly. But if I just let it ride it will overshoot.
Another odd thing is that when I autotune it the PID seems to work fine right afterwards. If I try and raise the temp after autotuning to a higher set temperature without first turning the PID off, it doesn't overshoot. But when I come back on brew day and use it to hit my mash temp, it overshoots.
Any thoughts? I'm ready to throw this thing out the window.
Cheers.
Dan