Rockwell Automation 1771-QDC, D17716.5.85(Passport) MNL. PLASTIC MOLDING MODULE - Manual (Page 83)

Load Initial Configuration Values
Chapter 7
7-14
Type of PID Algorithm
( INC02, PKC02, HDC02, and PLC02)
When executing pressure or screw RPM versus position or time profiles,
the QDC module can use one of two types of PID algorithms: dependent
gains (ISA) or independent gains (Allen-Bradley).
If B07(B03) = : Then it uses:
0 Dependent Gains (ISA)
1 Independent Gains (AĆB)
Dependent gains (ISA):
Output = Kc[(E) + 1/Ti
o
∫ t (E)dt + Td*d(E)/dt]
Independent gains (AB):
Output = Kp(E) + Ki
o
∫ t (E)dt + Kd*d(E)/dt
Comparison of Gain Constants
Compare dependent and independent gains constants as follows:
Dependent Gains Constants: Independent Gains Constants:
Controller Gain Kc (dimensionless) Proportional Gain Kp (dimensionless)
Reset Term 1/Ti (minutes per repeat) Integral Gain Ki (inverse seconds)
Rate Term Td (minutes) Derivative Term Kd (seconds)
Other variables used in any algorithm choice include:
Output = Percentage of full scale
E = Error (scaled) SP-PV (Setpoint-Process Variable)
PV = Process Variable (scaled)
Convert from dependent to independent gain constants by substituting
controller gain (Kc), reset (1/Ti), and rate (Td) values in these formulas:
Kp = Kc unitless
Ki = Kc
60 Ti
inverse seconds
Kd = Kc(Td)60 seconds
We recorded bit B07 (B03) = 1 for A-B independent gains on all
corresponding worksheets.
Select the Type of
PID Algorithm