12
UTILITY PARAMETERS
The Utility Parameters are grouped on PAGE-33 and allow the user to set the Compressor Control Strategy and the Zero-
Offset values for Temperature and the Relative Humidity (RH) values. The Table 8.1 below describes each parameter.
Table 8.1
Dry Bulb SP
Dry Bulb PV
(Default : Dry Bulb SP)
ZERO OFFSET FOR RH VALUE
This value is algebraically added to the measured %RH value to
derive the final PV that is displayed and compared for alarm /
control.
ZERO OFFSET FOR WET BULB
TEMPERATURE VALUE
This value is algebraically added to the measured Wet-Bulb
Temperature value to derive the final PV that is used to compute
the % RH Value.
ZERO OFFSET FOR DRY-BULB
TEMPERATURE VALUE
This value is algebraically added to the measured Dry-Bulb
Temperature value to derive the final PV that is displayed and
compared for alarm / control.
-25.0 to +25.0%
(Default : 0.0)
-25.0 to +25.0°C
(Default : 0.0)
-25.0 to +25.0°C
(Default : 0.0)
Parameter Description
Settings
(Default Value)
COMPRESSOR CONTROL STRATEGY
Refer detailed description below.
Compressor Control Strategy
The controller offers two different control algorithms for switching the compressor through Output 3 (OP3) Relay / SSR module
using the parameter ‘Compressor Control Strategy’. The two strategies are explained below. Note that either strategy
operates (switches ON/OFF) the OP3 only if the parameter ‘OP3 Function’ on PAGE-13 is set to ‘Compressor’ and the
‘Compressor Operation Mode ( CP.OP )’ parameter on PAGE-1 is set to ‘Auto’.
1. Dry Bulb SP Strategy
In this strategy, the controller provides two user settable parameters, viz.
Compressor Setpoint
(CP.SP) &
Time Delay
(t.dLY) in PAGE 13 parameter list.
The Compressor ON or OFF state is determined based on the relative position of the Dry Bulb SP (Temperature Setpoint)
with respect to the
Compressor Setpoint.
If the Dry Bulb SP is below the Compressor Setpoint, the compressor remains ON
and if the Dry Bulb SP is equal or above the Compressor Setpoint, the compressor remains OFF. The following Figures 8.1
and 8.2 illustrate the compressor ON and compressor OFF operation respectively.
User Manual
HumiTherm-c (Dry-Wet)
Section 8