[CcrPltMod21] Plant mode determination for cooling circuit

Determines the plant operating mode by considering various possible sources (e.g., scheduler, manual operation, room unit).

The operating mode is shown on BACnet with a multistate calculated value "Present operating mode" with the states "Off" and "On".

A parameter in the program is preset to prevent the plant from running. This is useful for testing data points. It must be switched off to start the plant.

"Startup function and alarm handling" controls the startup behavior of the plant after power-on. There is a delay after startup, "DlySttUp", of about 50 seconds. Do not change this delay. Change the delay, "DlyOn", so that it is different for each plant. This ensures that plants start one after another and do not overload the electrical system. There is also a collection and aggregation of all faults and alarms from the plant. If a local alarm lamp and/or reset button is required, an alternative can be selected.

This program block has the following optional functions:

Option: Condensation monitor (1xBI)

Reads the signal from a condensation monitor and stops the plant.

Option: Dew point temperature calculation (2xAI)

Creates analog inputs for room air temperature and room air humidity and reads their signals. Based on this information, it calculates the dew point temperature and adds an offset, e.g., 1 K. The resulting dew point temperature is displayed as an analog calculated value.

Option: External off

Interface that can be connected to a program logic for shutting down the plant.

Option: Flow temperature setpoint for cooling

Analog configuration value for flow temperature setpoint for cooling. This is required when only a binary cooling request is collected via a coordination function or for applications without coordination.

Option: Operating mode switch (1xMI=2xBI)

Reads the state of an operating mode switch, normally at the front of the electrical panel, and has the states "Auto", "Off", and "On".

Option: Operation indication (1xBO)

Commands a lamp (usually green) that turns on if the plant is running or that blinks if a switching operation is in progress.

Option: Outside air temperature (1xAI)

Creates an analog input for outside air temperature and reads its signal.

Option: Scheduler

Scheduler of type MSCHED with the states "Off" and "On" that switches the plant off and on.

Even with two states only, this is a multistate scheduler (not binary) that can be extended more easily if the project requires it.

See also

• Predefined I/Os
• Trend types
• Module families

See also

• Predefined I/Os
• Trend types
• Module families