Two Probe Hysteresis Freezer Control
Posted: Wed Jun 20, 2018 2:29 pm
Hi.
I have an old STC-1000 flashed to STC-1000+ firmware and it supports two probe freezer control, where one probe is in a TW in the fermenter and the other is reading the freezer temp. It functions like a kind of cascade control where it would run the freezer to the hysteresis/setpoint values unless a second hysteresis value was exceeded - this would prevent overshoots in temperature or freezeup of wort adjacent to the fermenter wall.
Is there an elegant way to do this in the BCS? I have seen where the second hysteresis value would would be an exit condition that sends you back to the cooling delay state and presumably would keep you there until the freezer temp was above its minimum and could continue.
Has anybody done this? Does it work well? Would you set the exit like a hysteresis (like 20F below setpoint) or simply just at a minimum (say 32F) to prevent freezing?
How does it work for ramping mode? I assume only the control setpoint is actually modified?
Best Regards
elburro
I have an old STC-1000 flashed to STC-1000+ firmware and it supports two probe freezer control, where one probe is in a TW in the fermenter and the other is reading the freezer temp. It functions like a kind of cascade control where it would run the freezer to the hysteresis/setpoint values unless a second hysteresis value was exceeded - this would prevent overshoots in temperature or freezeup of wort adjacent to the fermenter wall.
Is there an elegant way to do this in the BCS? I have seen where the second hysteresis value would would be an exit condition that sends you back to the cooling delay state and presumably would keep you there until the freezer temp was above its minimum and could continue.
Has anybody done this? Does it work well? Would you set the exit like a hysteresis (like 20F below setpoint) or simply just at a minimum (say 32F) to prevent freezing?
How does it work for ramping mode? I assume only the control setpoint is actually modified?
Best Regards
elburro