[FrPrt21] Frost protection
Program block, name / node subtype: [FrPrt21] Frost protection
Library hierarchy: Ventilation and air conditioning equipment
Family: FrPrt
Project tree | Diagram |
|---|---|
|
|
|
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.
Performs frost protection for a heating coil.
This program block has the following optional functions:
Option: Frost protection air controller (1xAI)
Measures the air temperature after the heating coil.
If the temperature drops below a certain setpoint, e.g., 12 °C, a PID controller sends a signal that can override the valve position of the heating coil.
If the temperature drops below the point for frost protection, an alarm is generated.
The AI is preset for reading the air temperature from a frost detector such as QAF63.xxx and has an effective range 0...15 °C.
Option: Frost protection monitor (1xBI)
Reads the binary output of the frost detector and generates an alarm.
Option: Frost protection water controller
Reads the return temperature of the water in the heating coil and maintains it at a certain setpoint by overriding the valve position of the heating coil. The setpoint changes if the plant stops. For example, it is 10 °C when the plant runs and 20 °C when the plant is off.
Upon an alarm from this program block, the program logic in the heating coil and in the air handling unit ensures that the plant stops, and the valve in the heating coil opens, and the pump starts. All the outputs are commanded with higher priority.
Name | Description | Type | Alarm / Notification class | Trend / Type |
|---|---|---|---|---|
|
FrPrtMon | Frost protection monitor | BI: Binary input | Yes, 4 | No |
FrPrtCtrW | Frost protection water controller | Ctr: Controller | N/A | N/A |
FrPrtCtrA | Frost protection air controller | Ctr: Controller | N/A | N/A |
Further elements that belong to this element: TFrPrtA | Frost protection for air temperature | AI: Analog input | Alarm: Yes | Notification class 4 | Trend type: 2 | ||||