mguterman Senior Member Joined: 10 Dec 2002 Posts: 24 Location: West Haven, CT Expertise: I live coffee
Espresso: Isomac Amica Grinder: Mazzer Mini Vac Pot: Bodum Drip: Melita single cone Roaster: Hottop
Posted Sun May 16, 2004, 8:35am Subject: I really need help with PIDing Amica
I have all the bits and pieces to PID Amica. Sadly, my liberal arts education has left me unprepared to set the PID device. I have the manual, but I can't figure out what they are talking about. Would someone who has done this please give me the various values that have to be plugged in. I can go through the book and press the buttons and change values, but since I have no idea what the various values affect, I have no idea of what to do. If this is too complicated to put on the forum and you are still willing to help, feel free to write me directly.
Yes, I have the same unit you do. I have essentially the same stuff you do, except that I got a 50 amp SSR with heat sink, which we are mounting outside the case. My machine is on all the time and the specs on the SSR suggested that inside with no heat sink might me problematic.
dcbrown Senior Member Joined: 13 Jan 2004 Posts: 166 Location: Chicago Expertise: I love coffee
Espresso: PID Zaffiro Grinder: Innova i1d
Posted Sun May 16, 2004, 7:54pm Subject: Re: I really need help with PIDing Amica
Michael
I think these are the only settings your likely to need to fiddle with.
rc = 1 second (cycle time...heating element will blink on at this rate) P-F = F (set for degrees F) P-dP = 1 (for 1 decimal digit display) P-SL = 32F (temp measuring range - low) P-SU = 300F (temp measuring range - high) CTRL = FUZY (if you want fuzy logic...recommended)
P-dF = 1.2 seconds (time constant of input filter)
(shorter duration temp changes than P-dF are treated as noise. Don't use the 5 second time recommended in the manual, it will respond too slowly to changes)
The following, P, i, and d, are tuned for each installation. They will control how aggressively the controller will seek its setpoint. They can be set automatically with autotuning, or you can fiddle. Mine is set up very nearly to proportional only control, and is not really optimized for my new thermocouple location.
P = 8.2 (% of range...as defined by P-SL and P-SU) i = 300 seconds (smaller number would be more aggressive) d = 0.0 (I have derivitive turned off for now)
AT = (set to 1 to start autotuning, but normally will be 0)
dcbrown Senior Member Joined: 13 Jan 2004 Posts: 166 Location: Chicago Expertise: I love coffee
Espresso: PID Zaffiro Grinder: Innova i1d
Posted Sun May 16, 2004, 8:28pm Subject: Re: I really need help with PIDing Amica
Here's my attempt at clarification on P, i and d values. I left this out of my main response, because you don't really need to know this, especially if you use autotuning, which I'd recommend.
P is the Proportional Band. It defines a range of temps near the setpoint where proportional control is used. Below this band the controller is 100% on, and above it is 100% off. If set too low you'll have overshoot and bounce. If set too high you'll sag below the setpoint and never reach it. Once you start fiddling with i and d this relationship is less clear. P is a percentage of the full scale. Don't compare P values with someone unless you know they have the same range defined (by P-SL and P-SU). Mine is set to 32F to 300F, so P=8.2% gives a 22F range.
i is integral time (reset time) and d is derivitive time. They both effect how frequently the controller readjusts to reach the setpoint. Smaller values of i and d will result in a more aggressive control, but can result in overshoot and bounce if set too low. In general, erratic behavior can be reduced by using larger values for i and d. Values for d are typically close to half of the i value.
For i and d, 0.0 is "OFF", a large value is weak, or nearly off, and a small non-zero value is strong. In other words, zero is the same as an infinitely large value. So Don't change from 0.0 to 0.1 ....it won't be a small change!
My settings are pretty conservative, mainly because I had problems with overshoot when the thermocouple was in the well. I haven't felt the same urgent need to refine the tuning now that the TC is on the side of the boiler.
AndyS Senior Member Joined: 10 May 2003 Posts: 474 Location: NY
Espresso: Tricked-out Silvia Grinder: Robur, M3, Mazzer Mini Vac Pot: Yama Drip: no, I don't have a Clover... Roaster: PIDed Popper
Posted Mon May 17, 2004, 6:45pm Subject: Re: I really need help with PIDing Amica
dcbrown Said:
i is integral time (reset time) and d is derivitive time. They both effect how frequently the controller readjusts to reach the setpoint. Smaller values of i and d will result in a more aggressive control, but can result in overshoot and bounce if set too low. In general, erratic behavior can be reduced by using larger values for i and d. Values for d are typically close to half of the i value.
For i and d, 0.0 is "OFF", a large value is weak, or nearly off, and a small non-zero value is strong. In other words, zero is the same as an infinitely large value. So Don't change from 0.0 to 0.1 ....it won't be a small change!
This is only partially correct. For integral time on the Fuji controllers, yes, 0.0 is off and a large value is weak. For derivative time, 0.0 is off, but large values are strong!
When you autotune, you'll see that the Fujis return a derivative time that is about one fifth the integral time. If you're manually tuning, unless you have a lot of experience, it's probably better just to leave the derivative off (set at 0.0).
AndyS Senior Member Joined: 10 May 2003 Posts: 474 Location: NY
Espresso: Tricked-out Silvia Grinder: Robur, M3, Mazzer Mini Vac Pot: Yama Drip: no, I don't have a Clover... Roaster: PIDed Popper
Posted Mon May 17, 2004, 6:52pm Subject: Re: I really need help with PIDing Amica
dcbrown Said:
Here's my attempt at clarification on P, i and d values. I left this out of my main response, because you don't really need to know this, especially if you use autotuning, which I'd recommend.
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