[Ccl24] Direct expansion evaporator cooling coil, temperature-controlled, humidity-controlled
Program block, name / node subtype: [Ccl24] Direct expansion evaporator cooling coil, temperature-controlled, humidity-controlled
Library hierarchy: Ventilation and air conditioning equipment
Family: Ccl
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Configurator
Program blocks are stored in the library without I/Os. Use the auto-create and auto-connect functions to create I/Os and/or to connect them to the interface blocks, e.g., R_A, CMD_B. Alternatively, take the I/Os from the folder containing the predefined I/Os in the library and/or from the plant and connect them to the interface blocks.
Controls the supply air temperature (cooling) and the supply air humidity (dehumidification) by modulating an output signal to the control unit of the direct expansion cooling coil (OutItf21). Alternatively, a request for different stages can be sent to the control unit of the cooling coil (OutItf22).
The control of the supply air humidity (dehumidification) is preset for absolute humidity (HuCtr21). You can change it to relative humidity in the Function configurator.
There is a delay off time, e.g., 5 minutes, for the signal for the operating state that keeps its value to "True" after the cooling coil becomes inactive. Both operating states of the valve and the optional pump equal to "False". If used in an air handling unit plant (which is most likely the case), the operating state of the cooling coil is read by CMDSEQ_B. If the plant is about to be switched off and the cooling coil was active, then the plant runs for some time with a cooling coil switched off to dry the coil. During the switch-off, CMDSEQ_B receives the operating state "True" for the length of time of this delay and waits there before continuing with the switch-off. This helps to dry the coil.
If the humidity controller is active, a calculated value indicates that the dehumidification process is active. This information is read by other components in the air handling unit, e.g., by the heating coil and the energy recovery, and their temperature control is blocked.
This program block has the following optional functions:
Option: Disable cooling at low outside temperature
Cooling and dehumidification are disabled below a certain outside air temperature, e.g., below 12 °C.
Option: Fault (1xBI)
Reads the fault signal from the control unit and generates an alarm.
Option: Feedback (1xBI)
Reads the feedback signal from the control unit and generates an alarm if feedback is missing when the coil must run.
Option: Flow detector (1xBI)
Reads the signal from a flow detector and releases the output interface and the control.
Option: Maintenance switch (1xBI)
Reads the signal from the maintenance switch and generates an alarm. If active, the outputs are stopped with very high priority (priority 2).
Name | Description | Type | Alarm / Notification class | Trend / Type |
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OutItf | Interface output | N/A | N/A | |
TCtr | Temperature controller | Ctr: Controller | N/A | N/A |
HuCtr | Humidity controller | N/A | N/A | |
DhuActv | Dehumidification active | BCalcVal: Binary calculated value | No | No |
Name | Description | Type | Alarm / Notification class | Trend / Type |
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Flt | Fault | BI: Binary input | Yes, 4/5 | No |
MntnSwi | Maintenance switch | BI: Binary input | Yes, 5 | No |
Fb | Feedback | BI: Binary input | No | No |
FlDet | Flow detector | BI: Binary input | No | No |
The extension for alarming for the predefined I/O for the optional element "Feedback" must be deactivated.
Description |
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Disable cooling at low outside temperature |