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CHC PID
Purpose
Configure the variables for closed loop control. PID
parameters can be set separately for both heating and cooling
control.
Mode
Configuration can be performed with the wizard Off-line or
On-line.
Procedure
1. Click the PID button on the left pane to open the PID
Configuration page.
2. Enter information into available fields.
3. Click Commit to save the settings or Reset to revert to
the last saved settings.
4. Click Next to display the Wiring Configuration page or
Back to display the Miscellaneous Configuration
page.
CHC PID settings
Table 12 describes the settings.
Energy Management
DLC SetPoint Bump
For load shedding applications, define the temporary setpoint shift to be added to the setpoint when the controller
receives a Load Shedding command. By raising the setpoint during cooling operation, or reducing the setpoint
during heating operation, the controller reduces the amount of heat or cool energy dissipated as a contribution to
load shed algorithms. The parameter can be set in the range 0 to 10DDC (0 to 18DDF).
Cool. Rec. Ramp, Heat. Rec. Ramp
Define the rate at which the setpoint is reset during changes between occupancy modes to provide a form of
optimum start algorithm
Table 11. CHC - Miscellaneous Options. (Continued)
Name Option and Definition
Table 12. CHC - PID Settings.
Name Setting and Definition
PID
Cooling/Heating
Allows the algorithm control parameters to be configured.
Proportional band
This value is the temperature deviation between setpoint and space temperature, which causes the control
output to modulate from 0% to 100% of full range. The variable can be set in the range 2 to 100DDC (3.6 to
180DDF), 1.3 to 100DDC (2.3DDF to 180DDF) for Proportional Control only.
Reset Time
This value is the integral reset time in the range 0 to 3200 sec. Setting the Integral constant to zero disables
integral operation.
Derivative Time
This value is the derivative constant in the range 0 to 3200 sec. Setting the derivative constant to zero disables
derivative operation.
Thermal Switching Band/PID Boost
Cooling/Heating
Boost Temp
Allows a boost band to be set for normal PID operation and when using thermal actuators. The variables indicate
a setpoint-space temperature deviation outside which the outputs are switched to full operation to act as a boost
function when space temperature deviates significantly from the desired setpoint. This band also serves as a
threshold for two-point switching of thermal actuators. The threshold can be set in the range 0 to 10DDC (7.2 to
180DDF). If the threshold is set to 0DDC, the boost function is disabled.