[HumTCtl21] Humidifier temperature-controlled
Program block, name / node subtype: [HumTCtl21] Humidifier temperature-controlled
Library hierarchy: Ventilation and air conditioning equipment
Family: HumTCtl
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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) by modulating an output signal to the control unit of a humidifier (OutItf21). Alternatively, request for different stages can be sent to the humidifier (OutItf22).
The most likely location of this humidifier is in the extract air.
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.
This program block has the following optional functions:
Option: Disable cooling at low outside temperature
Cooling is disabled below a specific outside air temperature, e.g., below 12 °C.
Option: Disable cooling at low temperature difference
Cooling is disabled if the temperature difference between the outside air temperature and the extract air temperature before the energy recovery is too low, e.g., below 4 K.
Option: Fault (1xBI)
Reads a fault contact and generates an alarm.
Option: Feedback (1xBI)
Reads the feedback signal and generates an alarm if feedback is missing when the humidifier must run.
Option: Limitation by relative humidity
PID controller that limits the output of the temperature controller if the extract air relative humidity before the energy recovery reaches, e.g., 90 %.
Option: Limitation by wet bulb temperature
PID controller that limits the output of the temperature controller if the extract air temperature before the energy recovery reaches the wet bulb temperature calculated from the extract air temperature and relative humidity.
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 |
|---|---|---|---|---|
TCtr | Temperature controller | Ctr: Controller | N/A | N/A |
OutItf | Interface output | N/A | N/A |
Name | Description | Type | Alarm / Notification class | Trend / Type |
|---|---|---|---|---|
Fb | Feedback | BI: Binary input | Yes, 4 | No |
MntnSwi | Maintenance switch | BI: Binary input | Yes, 5 | No |
LmCtr | Limitation controller | Ctr: Controller | N/A | N/A |
Flt | Fault | BI: Binary input | Yes, 4/5 | No |
Description |
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Disable cooling at low outside temperature |
Disable cooling at low temperature difference |
Limitation by relative humidity |
Limitation by wet bulb temperature |