Sensors; Sensor Specifications - Carrier CCU Regelungshandbuch

9 - CONTROL
- Operation in free cooling mode
W (chilled water) units
• Return air temperature sensor: Progressive operation of motorised dampers then the three-way valve.
• Air supply temperature sensor: limitation of the three-way valve then the FRESH AIR damper.
X (direct expansion) units
• Return air temperature sensor: progressive operation of the dampers (condensation units off).
• Supply air temperature sensor: FRESH AIR damper limit
■ Control of the "Target" relative humidity
This is proportional or proportional integral.
- Dehumidification control
The master control is increased if the relative humidity exceeds the setpoint. This value is broken down according to the parameter
settings (unit type parameter) and is:
• Staged for condensation unit control.
• Progressive for the chilled water valve control.
• Staged for indicating that the upper relative humidity limit has been exceeded.
Depending on the strictly proportional composition of the unit, a discrepancy may remain between the setpoint and the measurement, even
with all the elements at 0.
This control is limited by the lower drift of the target temperature.
NOTE: If the cooling and dehumidification controls control the same component, it is the largest value which counts.
- Humidification control
The master control is increased if the relative humidity drops below the setpoint.
This value is broken down according to the parameter settings (unit type parameter) and is:
• Progressive for the humidifier control.
• Staged for indicating that the lower relative humidity limit has been exceeded.
Depending on the composition of the unit, as strictly proportional, a discrepancy may remain between the setpoint and the
measurement, even with all the elements at 0.

10 - SENSORS

Sensor specifications:

■ NTC temperature sensor
- Measurement range: -40 to 99.9 °C
- Tolerance: ± 0.2 °C from 0 to 70 °C
- Thermistor: NTC 10 k at 25 °C reference 10K3A1
- Adjustment of the controlled and outdoor temperature sensors from -5 to +5 °C (reserved for the manufacturer access level)
Example of adjustment on controlled temperature:
1. Reading parameters (menu 3.3) ENTER
2. Cursor opposite parameter P255 Controlled temperature ENTER
3. Modify the adjustment (-5 to 5 °C)
4. Confirm with the ENTER key
- Failure to connect, wire cut or short circuit feedback
The fault is displayed. It stops the corresponding controls and controllers
For example, the "outdoor sensor" fault can stop the free cooling control.
It is released automatically.
■ 2-10 V temperature sensor
- Measurement range: -40 to 100 °C
- Low value adjustable at 2 V: from -40 to 99.9 °C
- High value adjustable at 10 V: from -40 to 99.9 °C
- Linear scale between 2 and 10 V
- Sensor fault indicated if the measurement value is < 1.5 V
The fault is displayed and the control switches to the controlled temperature sensor (NTC) with specific setpoints for the 2-10 V
sensor fault.
It is released automatically if the measurement value is >2.0 V
■ Humidity sensor 0-10 V
- Measurement range: 0 to 100 %
- Adjustment of the controlled and outdoor humidity sensor from -10 to 10 % (reserved for the manufacturer access level)
■ Filter differential pressure sensor:
- Measurement range if P35 = 0 : 0-10 V 0-1000 Pa
- Measurement range if P35 = 1: 0.5-4.5 V 0-1000 Pa
■ Fan differential pressure sensor:
- Measurement range 0: 0-10 V 0-2500 Pa
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