This FAQ is an aid to selecting suitable values of KP, KI, KD when the Time Constants of the Generator and Exciter are unknown. If the Time Constants of the Generator and Exciter are known they can be entered directly into the PID Calculator in the Bestcoms configuration software and suitable values of PID will be automatically calculated.
The stability ranges 1 to 20 are preset values that are embedded in the firmware of the DECS100 and can only be accessed when communicating with the DECS. Range 21 can be selected in BESTCOMS when not connected to a DECS unit and it enables access to the PID window to customise these values.
We suggest that the following settings be used for initial start-up which should result in stable voltage for most if not all applications. The response may be sluggish but the goal is to not cause drastic voltage swings when the generator is first started.
To tune the DECS-100 to the desired response with these numbers, it is expected that you would only need to adjust the AVR Kg. Increasing or decreasing the AVR Kg value as if it was a stability potentiometer. In some cases, the Kd term may have to change however this is unlikely to be the case in most applications.
KP = 80
KI = 20
KD = 5, or 10
TD = 0
AVR Kg = 50
FCR Kg = 100
OEL Ki = 10, Kg = 1
UEL Ki = 4, Kg = 1
VAR/PF = Ki = 3, Kg = 1
Please share your feedback and experiences as we can use it to make further adjustment to these pre-settings.