I am working on dialing in the PID settings on a Furnace using RS Logix500 I know what Gain, Reset, and Rate are but I am not sure of some of the other settings do like loop update, the input values, and the flags. Any help would be appreciated
PID (Proportional Integral Derivative) is a control algorithm which is used to keep a Process Variable at the Setpoint value by varying the Control Variable.
Use the RSLogix 500 Menu bar, Help, Instruction Help, PID information for the description of the PID parameters and functionality logic.
Be careful before you go too far into tuning; this is a lengthy process requiring quite a few trial and error steps.
Oh trust me I know this isn't my first rodeo with PID settings I already understand what they are and what the Gain, Reset, and Rate are. I couldn't find the loop update and stuff as our other controllers don't use those they just use Gain, Rate, and Reset(it also autotunes which makes life way easier). I found the descriptions now, and I figure I will be doing this for awhile this furnace chart looks like and A/C graph so it has to be done
Auto is not a setting but a mode of operation for the instruction.
When tuning is being performed the PID instruction is in Manual mode- the user is controlling the PID output (the PID algorithm result does not affect the Control Variable value, the programmer does)
When done with the manual loop tuning set the PID instruction to Auto mode and the instruction will vary the Control Variable as intended.
So when I am running the furnace in the Manual setting the PID settings aren't actually being used? That is way different than how it was explained to me before.
Since you guys have been so helpful I thought I would post a resource I found that made programming this PID very easy, Tom Tella's Simplified Guide to P-I-D Temperature Control, it does a great job of explaining and gives excellent formulas for figuring values, if anyone has to program a furnace PID this is a great resource to use.