LG LCWW, Operation & Maintenance Manual

Page: 46 / 119

P. I. D temperature control
Unique P(proportional), I(integral) and D (differential) algorithms are applied to control the chilled water temperature to
minimize the access time to the target value (in contrast to the conventional method), residual deviation and the
Under-Shoot and Over-Shoot in initial startup and when the conversion between automatic operation and manual op-
eration is made, executing the optimum control.
46
4. CONTROL SYSTEM
ENGLISH
Controlled value
Target value
Controlled value
Target value
The target can be approached smoothly.
<Conventional control method> <New P. I. D control by LG>
(1) Chilled water outlet temperature
The menu is for setting P. I. D control temperature of the chilled water outlet in air conditioning operation.
The temperature is the target control value in P.I.D control operation.
In the scheduled operation mode, this item is not displayed.
(2) Chilled water temperature P value (Proportional)
In air conditioning operation, P value in the proportional control zone is set which is used for PID control of the
chilled water.
(3) Chilled water temperature I value (Integral)
In air conditioning operation, I value in the integral control zone is set which is used for PID control of the chilled
water.
(4) Chilled water temperature D value (Differential)
In air conditioning operation, D value in the differential control zone is set which is used for PID control of the
chilled water.
(5) Chilled water outlet temperature - ice making
Menu to set the chilled water outlet control temperature in the ice making mode
(6) Cooling tower fan step control
This operation mode is used for the cooling tower fan control to stabilize the cooling water inlet temperature.
The standard operation method is for running and stopping one unit of cooling tower fan in the chiller control
panel.
!
CAUTION
Before setting, check the specifications provided in the cooling tower fan motor.
When connecting the cooling tower to micom, check first the daily possible operation frequency and re-startup
possible time of the cooling tower fan motor, and then make the settings. In case there is an error in the set-
ting, the operation of the cooling tower fan motor can be stopped due to the motor damage or superheating.
When the settings of Main menu/System Menu/Safety control setting/Cooling tower control select are done in
steps, the cooling tower fan control is done in steps accordingly.
Figure 29 Control method comparison