Is it supposed to run the process or just force the output on?
My program for a fermenter, The first two states should loop and just check temp every 15 min. If it determines temp > 50 starts output 4 (in deferential mode set at 50) compressor till temp <=48 at which time it should turn off compressor and start looping again.
state0 wait exit0 =0 (counts down from 15:00) exits to state1 hold timer0 counts down from 15
state1 hold exit0 temp > 52 exits to state2 chill, exit1 temp<48 exits to state0 (wait) timer 1 counts up in this stage
state 2 chill controls output 4 in differential mode at a setting of 50 degrees time2 counts up in this stage
So what happens when power is restored (lost it last night), timer0 counts down from 15, exits to state1, and keeps looping, However when power was restored it started up with output 4 on (which I do not want, hence the 15 min countdown,) and never turned it off (the timer was up to over 14 hours)
Is the fix to eliminate state1? Would output 4 in differential mode cycle the compressor on and off without state changing? Then would it have an exit condition?
Is it possible to have the alarm function associated with a temp?
how is procforce at startup supposed to work?
Re: how is procforce at startup supposed to work?
I also notice that under the edit process tab, select state0, in the current state tables box output 4 has a check mark under directly controlled on/off, I try to clear it select apply, but it just comes back. The control box is not checked.
Re: how is procforce at startup supposed to work?
Can you attach your process config file? I'd like to load it and test it out.
Re: how is procforce at startup supposed to work?
Did it come thru?
thanx
thanx
- Attachments
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- bcs_proc.cfg
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Re: how is procforce at startup supposed to work?
Thanks for posting. I loaded it up on the demo, process2. http://ecc.webhop.org:8081 if anybody wants to take a look.
At first glance it your process looks good, it should accomplish exactly what you want it to. I wonder if this isn't related to the same bug gbrewer pointed out in the 'unclean exit' thread. Which timer was running away, and which state was it stuck in? I'll do some experiments here to see if I can recreate it.
To answer your question, setting Out4 to differential control at 50deg will cycle the output while its in the Chill state. However the the way its currently setup the exit condition will fire before the differential control gets a chance to turn it off. Diff control would try to chill it to 48 (setpoint - swing/2) but the exit condition sends the process back to the wait state when it hits 50. So my guess is the temperature will (slowly) bounce around 50-52 with this program.
As simpler solution might be to have a single state process, and let the differential control handle the switching. If you set it to 50deg with a 4deg swing, it will automatically hold it to that temperature. The large swing setting will ensure that it doesn't switch too often. If you want even more assurance that it won't switch too fast, you can bump out the PID Sample Period to 60seconds or so. That parameter sets how BCS reads the temperature to decide to turn an output on/off. But I wouldn't go too much higher than 1min, because it also affects how long to hold an output on before checking again.
However the way that you have it programmed does give you more detailed control. Using the 3 states will guarantee it waits 15min after the cooling cycle, well done.
At first glance it your process looks good, it should accomplish exactly what you want it to. I wonder if this isn't related to the same bug gbrewer pointed out in the 'unclean exit' thread. Which timer was running away, and which state was it stuck in? I'll do some experiments here to see if I can recreate it.
To answer your question, setting Out4 to differential control at 50deg will cycle the output while its in the Chill state. However the the way its currently setup the exit condition will fire before the differential control gets a chance to turn it off. Diff control would try to chill it to 48 (setpoint - swing/2) but the exit condition sends the process back to the wait state when it hits 50. So my guess is the temperature will (slowly) bounce around 50-52 with this program.
As simpler solution might be to have a single state process, and let the differential control handle the switching. If you set it to 50deg with a 4deg swing, it will automatically hold it to that temperature. The large swing setting will ensure that it doesn't switch too often. If you want even more assurance that it won't switch too fast, you can bump out the PID Sample Period to 60seconds or so. That parameter sets how BCS reads the temperature to decide to turn an output on/off. But I wouldn't go too much higher than 1min, because it also affects how long to hold an output on before checking again.
However the way that you have it programmed does give you more detailed control. Using the 3 states will guarantee it waits 15min after the cooling cycle, well done.
Re: how is procforce at startup supposed to work?
"Which timer was running away, and which state was it stuck in?"
Timer0 was counting down from 15 minutes, would hit 0 then restart counting down again (i assume it advanced to state1 seen temperature was low, then exited to state0 as it should have and continued counting
However, it must have been stuck in state2 as output 4 was on, which is only controlled by state2 and was never turned off. The timer (timer2) for that state was up over 14 hours and counting when I checked. temp was well below 0. (it should have turned off at 48. (Set point was 48 to change state, diff control was set at 50, and temp was maintaining between 48 and 52 for about 8 days prior to power loss). Power was lost, and when power was restored is where the problem showed up, as that is about the time timer2 started counting up. (lost power 8:30 p.m., it was restored about 2:30a.m., and I didn't check it till I got off work in the evening.
The main reason for the timers was it did this once prior, but I had no idea why. I do know that we definitely lost power this time tho, and had quite a few outages this summer ranging from a few seconds to 20+ hours.Maybe it was on when power went out, and it is related to same bug.
thans
Timer0 was counting down from 15 minutes, would hit 0 then restart counting down again (i assume it advanced to state1 seen temperature was low, then exited to state0 as it should have and continued counting
However, it must have been stuck in state2 as output 4 was on, which is only controlled by state2 and was never turned off. The timer (timer2) for that state was up over 14 hours and counting when I checked. temp was well below 0. (it should have turned off at 48. (Set point was 48 to change state, diff control was set at 50, and temp was maintaining between 48 and 52 for about 8 days prior to power loss). Power was lost, and when power was restored is where the problem showed up, as that is about the time timer2 started counting up. (lost power 8:30 p.m., it was restored about 2:30a.m., and I didn't check it till I got off work in the evening.
The main reason for the timers was it did this once prior, but I had no idea why. I do know that we definitely lost power this time tho, and had quite a few outages this summer ranging from a few seconds to 20+ hours.Maybe it was on when power went out, and it is related to same bug.
thans
Re: how is procforce at startup supposed to work?
I believe the runaway timer prob should be fixed in v3.2. Let me know if you still see issues.