Despatch LEB Series - Manual (Page 26)

18
Operating Parameter Outline
Code Name Settings
CtL Control Mode PID
At Auto-tuning OFF
P Proportional Band 4 (8 if
°°°°
F)*
I Integral Time 15
d Derivative Time 0
nr Manual Reset (only when I & d are OFF) N/A
HyS Hysteresis (only when CtL is ONF, change CtL to PID) N/A
Ct Cycle Time 1
FL Input Filter 0
bS PV Bias (Offset) 0
LoC Key Lock 1
*If P is not displayed the Control Mode (CtL) must be first set to PID.
CtL
Control Mode - This parameter determines whether controller functions as a
time proportional or an on/off control.
At
Auto-tuning – OFF for PID tuning, ON for controller to tune process.
P
Proportional Band - Expressed in degrees. This value determines the band
width on both sides of the setpoint within which the control provides
proportional control.
I
Integral Time - Expressed in seconds. This parameter corrects for errors in
actual temperature versus the setpoint.
D
Derivative Time - Expressed in seconds. This effect of the derivative time is
in direct proportion to the time setting.
nr
Manual Reset - Expressed in percent. Controller outputs this value when
process variable equals setpoint (Only if I = 0).
HyS Hysteresis - Expressed in degrees. When CtL = OFF, this value
determines the change in temperature needed to turn controller output from
full off to full on.
Ct
Cycle Time - Expressed in seconds. This is the total time for one ON/OFF
cycle of the controller output during the proportional action.
FL
Input Filter – Expressed in seconds. This function should be used when the
PV may fluctuate greatly (i.e. input signal contains noise).