Output Control (Direct On/Off)

Describe your system and processes, and post your config file.
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gidi-up
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Output Control (Direct On/Off)

Post by gidi-up »

Now looking at this it appears this might be a feature/function request but not 100% sure


So I have a boil kettle that has 4 heating elements (Yep), so with say Temp Probe 1 I can only control Output 1 in Hysteresis heat mode.

So what I have to do is:
Process Boil:
State 0 = Start to boil, enable outputs 0, 9, 10 & 11 (SO kick on all 4 elements)
State 0 exit condition = 'Temp probe 0' if => 214, then goto 'State 1', boil rest.

State 1 'Boil Rest', exit = 'Temp probe 0' if =< 210, then goto 'State 0', boil.


So I am continually looping through these 2 states, it works but not the greatest solution.


So it would be nice to control Outputs 8-17 with the Temp probe of my choosing...


So to go a bit deeper, I have 3 boil kettles, with 4 elements each and I seen in 4.0 you can control outputs 0-7 to a temp probe of my choosing BUT in order to do this I pretty much would have to have a dedicated BCS-462 for each Boil Kettle to run everything needed.


Thoughts?


Thanks

Jerry
JonW
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Re: Output Control (Direct On/Off)

Post by JonW »

If all 4 elements are firing together, just wire them all to the same output.
gidi-up
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Re: Output Control (Direct On/Off)

Post by gidi-up »

Well that is logical that is why :D

But @ process start it is nice to run all 4 elements to cut down time to boiling point, then when at boiling point I can run just 1,2 or 3 elements are required to keep a rolling boil. As kicking on all 4 after the boil is rolling might not be the most efficient.

So if every output could be controlled by the same probe I could set each element to a different temp to cut off, so run all elements to 208, then like every 2 degrees start dropping off elements. Then they would only kick on if the temp drops to low (Like when brewing in Winter time), this would save electric costs over time.


Thanks

Jerry
JonW
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Re: Output Control (Direct On/Off)

Post by JonW »

You're going to completely mess up the PID tuning of the probes/elements by adding or dropping elements into the heating pool. Again, I'd suggest firing all 4 at once. If they are all cut down to minimum PWM, then your tuning is going to work and you're still going to be saving electricity since their output will be minimal.
gidi-up
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Re: Output Control (Direct On/Off)

Post by gidi-up »

OK, understanding the logic behind this.

I have read up on PWM, but what is a value for "cut down to minimum PWM", not sure the mentioned 90% is as low as you want to go or is this just a adjust and learn as you go setting...

I am running 4 - 15kw, 208v 3ph elements, not sure that matters.


Thanks

Jerry
clearwaterbrewer
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Re: Output Control (Direct On/Off)

Post by clearwaterbrewer »

if you have all elements firing, but for 1% of the 2 second standard duty cycle, you will be at 1% power.... that would be minimum PWM

Also, if you decide to boil a wort that has high solids in it ( pumpkin in the boil, for example), your will have 1/4 the watt density when having 4 elements on 25% versus one on 100%...
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