User`s guide

106 MLS User’s Guide
Tuning and Control
General PID Constants
This section gives general PID constants.
Proportional Band Only (P)
Set the PB to 7% of the setpoint
Example
: Setpoint = 450, set the Proportional Band to 31.
Proportional with Integral (PI)
Set the PB to 10% of setpoint.
Example
: Setpoint = 450, set PB to 45.
Set TI to 60.
Set TD to Off.
Set the Output Filter to 2.
PI with Derivative (PID)
Set the PB to 10% of the SP.
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.
PB TI TD FIL OUTPUT CT Action
Electric heat with solid state
relays
50 60 15 4 TP 3 Reverse
Electric heat with mechani-
cal relays
50 60 15 6 TP 20 Reverse
Gas heat with motorized
values
60 120 25 8 DZC/DAC NA Reverse
Gas heat with motorized val-
ues (SP > 1200
°
F)
100 240 40 8 DZC/DAC NA Reverse
Extruders with cooling, Heat
with SSRs
50 300 90 8 TP 3 Reverse
Spread set to zero, cool with
solenoid valve
10 OFF OFF 4 TP 20 Direct
Cool with fans 10 OFF OFF 4 TP 60 Direct
Electric heat with open heat
coils
30 20 OFF 4 DZC NA Reverse
Electric heat with SCR con-
trollers
60 60 15 4 DZC/DAC NA Reverse