General pid constants, Proportional band only (p), Proportional with integral (pi) – Watlow MLS User Manual
Page 118: Pi with derivative (pid)
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