[HydCrtHC21] Hydraulic circuit for heating/cooling, flow temperature control
Program block, name / node subtype: [HydCrtHC21] Hydraulic circuit for heating/cooling, flow temperature control
Library hierarchy: Universal equipment
Family: HydCrtHC
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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 flow temperature.
The program receives flow temperature setpoints for heating and cooling and displays them on BACnet with two calculated value objects. It also receives a heating or cooling state signal and activates one of the two PID controllers to change the valve position to control the flow temperature. The pump runs when the function is enabled.
A parameter in the program defines if the plant stops when the flow temperature sensor has a fault.
The flow temperature has an alarm extension. A program logic changes the high limit dynamically (according to the heating cooling state).
This program block has the following optional functions:
Option: Demand
Generates hot water demand or chilled water demand and displays them with two BACnet calculated values.
Option: Frost protection
Checks if the flow or the return temperature are in alarm due to a low limit violation and generates an alarm with a binary calculated value. It deactivates all limits for the heating controller, changes the heating/cooling state to heating and activates the hot water demand.
This signal is read from the "Heating cooling changeover" (HCChovr21) in the plant mode determination of the heating/cooling circuit plant.
Option: Maximum controller output limitation
An interface reads the signal for charge priority limitation from a domestic hot water plant (over BACnet).
Option: Maximum return temperature limitation
A PID controller limits the return temperature to a maximum, depending on the outside air temperature. You can adjust the setpoint for the maximum limitation in a CHAR_LIN in the program.
Option: Minimum return temperature limitation
A PID controller limits the return temperature to a minimum.
Option: Overtemperature detector (1xBI)
Reads the signal from an overtemperature detector and generates an alarm. The program logic stops the temperature control and closes the valve. If the option "Pump delay after overtemperature" is active, the pump stops with a delay. Otherwise, the pump stops immediately.
Option: Pump activation at low outside temperature
The pump always runs below a certain limit for the outside temperature. This is to increase the frost protection.
Option: Pump delay off after overtemperature
Defines a delay off for the pump after overtemperature (signal from the overtemperature detector or from the safety temperature limiter or from the high limit alarm from the flow or return temperature). The reason for this is that in well-insulated pipes, the pump must run for some time to cool down the water. Otherwise, the plant recovers from the overtemperature condition very slowly.
Remove this option for floor heating or cooling.
Option: Return temperature (1xAI)
Creates an analog input for the return temperature and reads its signal. It can generate an alarm (high and low limit).
Option: Safety temperature limiter (1xBI)
Reads the signal from a safety temperature limiter and generates an alarm. The program logic stops the temperature control and closes the valve. If the option "Pump delay after overtemperature" is active, the pump stops with a delay. Otherwise, the pump stops immediately.
Option: Switch-off delay for pump
Defines a switch-off delay for the pump. It is preset to be short and is parameterizable in the program.
Name | Description | Type | Alarm / Notification class | Trend / Type | |
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TFl | Flow temperature | AI: Analog input | Yes, 4 | Yes, 2 | |
PrSpTFl(C) | Present flow temperature setpoint (Cooling and refrigeration) | ACalcVal: Analog calculated value | No | No | |
TCtrC | Temperature controller for cooling | Ctr: Controller | N/A | N/A | |
TCtrH | Temperature controller for heating | Ctr: Controller | N/A | N/A | |
PrSpTFl(H) | Present flow temperature setpoint (Heating) | ACalcVal: Analog calculated value | No | No | |
Vlv | Valve | N/A | N/A | ||
Pu | Pump | N/A | N/A | ||
Name | Description | Type | Alarm / Notification class | Trend / Type |
|---|---|---|---|---|
SftyTLm | Safety temperature limiter | BI: Binary input | Yes, 5 | No |
OvrTDet | Overtemperature detector | BI: Binary input | Yes, 4 | No |
FrPrt | Frost protection | BI: Binary input | Yes, 5 | No |
TRt | Return temperature | AI: Analog input | Yes, 4 | Yes, 2 |
Further elements that belong to this element: TRtCtrMin | Return temperature controller for minimum limitation | Ctr: Controller TRtCtrMax | Return temperature controller for minimum limitation | Ctr: Controller | ||||
ChwDmd | Chilled water demand | BCalcVal: Binary calculated value | No | No |
HwDmd | Hot water demand | BCalcVal: Binary calculated value | No | No |
Description |
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Pump activation at low outside temperature |
Pump delay off after overtemperature |
Switch-off delay for pump |
Maximum controller output limitation |