I am doing a testrun with my conical and I noticed something weird in the beer temperature sensor reading. When I change my setpoint from 22.5 to 23.5 the temperature reading from the beer changes with 1 degree also?!? When I change the setpoint back to 22.5 the temperature reading goes down with 1 degree agian…
For switching without the load, I meant disconnecting the load, not the SSR control signal.
Try keeping your high current load circuit completely separate from the control side.
Avoid that the return current for the heater goes through the same ground wire as the control side and the sensor side.
Each 12V wire going to the heater should have a GND wire right next to it.
12V supply plus --> SSR --> heater plus
12V supply minus <--------- heater minus
Think about which path the current takes and minimize loop area of the path. Especially avoid that the ground path runs through or past a different circuit. The current will follow the path of least resistance, you’ll want a ground wire going from the heater directly back to the power supply and right next to the 12V path.
The SSRs should have an optocoupler inside. So your paths for control and load can be completely separate and only optically coupled. No electric connection between them.
I just checked the voltage over the 5V and GND. I measured it at the bottom of the SSR control board on the soldering pads. The voltage is 4.73 with SSR off and 4.63 with SSR on. I checked all the RJ12 ports and the voltage is the same for all ports.
I have a new idea what the problem might be. I am no specialist in data communication but is it possible that due too short RJ12 cables reflection occurs and disturbs the data communication?
In my HERMS setup I still have the issue with the valves that does not respond sometimes. Here I have also a lot of short home made RJ12 cables…
From what cable did you make them?
My old brewing setup got a lot more reliable when I replaced the 6 wire phone cable with 8 wire CAT5e with only 6 of the 8 wires connected. Phone cables can be really thin and cat5 is much thicker. The cables I sell are made from CAT5.
It is also possible that making a cable a bit longer changes the resonance frequency and might actually improve things because the sensitivity to noise shifts in frequency.