Watlow ANASOFT - Manual (Page 75)

Appendix A: PID Tuning and
ANASOFT User’s Guide 65
General PID Constants by Application
This section gives PID values for many applications. They are useful as
control values or as starting points for PID tuning.
Proportional Band Only (P)
PB: Set the PB to 7% of the setpoint (SP) (Example: Setpoint = 450, so
Proportional Band = 31).
Proportional with Integral (PI)
PB: Set the PB to 10% of SP (Example: Setpoint = 450, so PB = 45).
Set TI to 60.
Set TD to Off.
Set the Output Filter to 2.
PI with Derivative (PID)
PB: Set the PB to 10% of the SP (Example: Setpoint = 450, so PB = 45).
Set the TI to 60.
Set the TD to 15% of the TI (Example: TI = 60, so TD = 9).
Set the Output Filter to 2.
The next table shows general PID constants by application.
Application PB TI TD Filter
Output
Type
Cycle
Time
Action
Electrical heat w/ SSR 50 º 60 15 4 TP 3 Reverse
Electrical heat w/ EM
relays 50 º 60 15 6 TP 20 Reverse
Cool w/ solenoid valve 70 º 500 90 4 TP 10 Direct
Cool w/ fans 10 º off 10 4 TP 10 Direct
Electric heat w/ open
heat coils 30 º 20 off 4 DZC - Reverse
Gas heat w/ motorized
valves
SP>1200
60 º
100 º
120
240
25
40
8 DAC or
SDAC
- Reverse
Electric heat w/ phase
angle controlled SCR 60 º 60 15 4 DAC or
SDAC
- Reverse
Extuders w/ cooling
gas heat w/ SSR (set
spread to 8) 50 º 300 120 4 TP 3 Reverse