chuckjaxfl
Well-Known Member
I should be starting on a three vessel, all electric system shortly.
The plan is to build the physical system all "manual" to begin, then continue adding automation, well, indefinitely, I suppose. I'll be using Arduino and the PID library, until my interests take me elsewhere.
The plan is for a 5500 watt HLT, a 5500 watt KET, then probably a 1500 watt RIMS tube. However, my power source is only 30A.
My plan is to have the "on time" for all three vessels computed each 2000 millis cycle, have the vessels fire sequentially, with one third of the remaining idle spread between each vessel's portion of the duty cycle.
For example, if the HLT PID computes 5%, the RIMS PID computes 6%, and the boil kettle PWM is set to 50%, then the firing order would be:
HLT on for 100ms, all off for 260ms, RIMS on for 120ms, all off for 260ms, KET on for 1000ms, all off for 260ms. Then read the sensors, recompute, and start over.
Obviously, the total off all three vessels couldn't exceed 100%. I would constrain the output of the second two vessels to 0 until the first vessel dropped below say, 95%, at which point it could start firing the second vessel, constrained to 3% (arbitrary numbers for now). As the duty cycle required to the first vessel continues to drop, the time available to the second vessel would increase. When the sum of those two drop, time would become available to the third vessel.
I intend to program a minimum delay between each vessel. Each cycle on the SSR is 8.3ms, so what do you guys think a safe margin is to ensure the "on" cycles don't overlap? Should 50ms be enough?
As a backup, in case something weird happens with the code, I'd route the output through a set of AND & NOT gates arranged so that only one of the three vessels could fire at once. And, of course, as a second backup there's always the 30a breaker itself.
I think this is a really viable option, but I haven't seen it done before. What do you guys think? In what order would you prioritize the vessels? I have ideas, but I'd like to read your thoughts. Also, what about the minimum dwell time between each vessel, 50ms too much? Not enough?
The plan is to build the physical system all "manual" to begin, then continue adding automation, well, indefinitely, I suppose. I'll be using Arduino and the PID library, until my interests take me elsewhere.
The plan is for a 5500 watt HLT, a 5500 watt KET, then probably a 1500 watt RIMS tube. However, my power source is only 30A.
My plan is to have the "on time" for all three vessels computed each 2000 millis cycle, have the vessels fire sequentially, with one third of the remaining idle spread between each vessel's portion of the duty cycle.
For example, if the HLT PID computes 5%, the RIMS PID computes 6%, and the boil kettle PWM is set to 50%, then the firing order would be:
HLT on for 100ms, all off for 260ms, RIMS on for 120ms, all off for 260ms, KET on for 1000ms, all off for 260ms. Then read the sensors, recompute, and start over.
Obviously, the total off all three vessels couldn't exceed 100%. I would constrain the output of the second two vessels to 0 until the first vessel dropped below say, 95%, at which point it could start firing the second vessel, constrained to 3% (arbitrary numbers for now). As the duty cycle required to the first vessel continues to drop, the time available to the second vessel would increase. When the sum of those two drop, time would become available to the third vessel.
I intend to program a minimum delay between each vessel. Each cycle on the SSR is 8.3ms, so what do you guys think a safe margin is to ensure the "on" cycles don't overlap? Should 50ms be enough?
As a backup, in case something weird happens with the code, I'd route the output through a set of AND & NOT gates arranged so that only one of the three vessels could fire at once. And, of course, as a second backup there's always the 30a breaker itself.
I think this is a really viable option, but I haven't seen it done before. What do you guys think? In what order would you prioritize the vessels? I have ideas, but I'd like to read your thoughts. Also, what about the minimum dwell time between each vessel, 50ms too much? Not enough?