1. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
Beckhoff Building Automation

2. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
In the following exercise is the programming of a heating circuit stepwise described.
Function:
This installation is a static heating circuit in which the flow temperature is controlled in accordance with the outside temperature.
The actuator for the heating circuit valve is a three-point actuator.
The heating circuit can be switched into night setback mode by a switching timetable.
Beckhoff Building Automation

3. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
The programming takes place with pre defined Macros.
The macros are composed of TwinCAT Export-Files:
The HVAC-Macros are located in the folder: ….\EXP_Files\subprograms. Fore a better overview the sub programs are classified in sub folders.
Beckhoff Building Automation

4. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
For using the macros there are some adjustments in TwinCAT necessary. At [Projekt] Options you get in the menu Editor from TwinCAT. There you have to adjust the fond and tab width.
Beckhoff Building Automation

5. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
To use the macros the following libraries must be included \TwinCAT\Plc\Lib\.
Beckhoff Building Automation

6. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
The base program must be loaded first before the macros can be used. The System programs folder is located within the base program. The programs are used to initialise global variables.
Please open the Projekt : Base_Program.pro
Beckhoff Building Automation

7. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
In the base program the following global variables are defined.
rOutside_T outdoor temperature
rOutside_T_damped outdoor temperature damped
bFlashFlag Blinker
CtrkVoltage V AC, 24V DC, 24V AC
bResetFault acknowledge faults
stSystemTime System time structure
dtSystemTime System time date an time
uiYear Year
uiMonth Month
uiDay Day
uiDayOfWeek Day of week (0-6)
uiHour Hour
uiMinute Minute
uiSecond Second
uiMillisecond Millisecond
tTaskCycleTime Cycle time Task
tPLCCycleTime Cycle time PLC
Beckhoff Building Automation

8. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
1. Step. Add a folder with the name HC1 (Heating circuit one)
Beckhoff Building Automation

9. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
2. Step:
Load all the macros for the heating circuit out of the folder: EXP_Files
Heating Valve: 3Point_CtrlValve with AntiblockageE__X_3PCtrlValve_AB.EXP
PID-Controller: PID_Ctrl__X_PID.EXP
Setpoint Calculation: Setpoint_Heating_Circuit __X_SETPOINT_HC.EXP
Time Schedule: TimeScheduling_1Stage__X_ TimeSchedul1St.EXP
Temperature Sensor: TemperatureSensor__X_T.EXP
Pump: Pump__X_PU.EXP
Beckhoff Building Automation

10. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
3. Step:
Rename all objects.
Replace the placeholder X with the plant name HC1.
Move all program blocks into the folder HC1
Result:
Beckhoff Building Automation

11. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
4. Step:
Create a main program for the heating circuit named HC1.
Beckhoff Building Automation

12. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
5. Step:
Place all subprograms from HC1 in the main program an connect them. See below!
0 -> 1 Time Scheduling transfers day or night modus
3 -> 1 Transmission freeze protection status for setpoint calculation.
1 -> 4 The heating is operating and enables the PID-Controller.
5 -> 4 The actual temperature value is transmitted to the PID.
4 -> 2 The PID is transmitting his control value to the valve.
4 -> 3 The controller is transmitting his output to request the pump depending on the valve position.
Beckhoff Building Automation

13. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
6. Step:
The heating circuit is finished now.
The call form HC1 is to add in Main.
Beckhoff Building Automation

14. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
Compile the program
Beckhoff Building Automation

15. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
Beckhoff Building Automation

16. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
Beckhoff Building Automation

17. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
Beckhoff Building Automation

18. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
Beckhoff Building Automation

19. HVAC-Library Exercise Heating Circuit
New Automation Technology
HVAC-Library Exercise Heating Circuit
If another heating circuit is required, it is very efficient to proceed as follows: The name of the heating circuit is underlined in red. With the text editor we search for HC1 and replace it with HC2. This renames all the program blocks in the heating circuit macro, and all the variables that are locally declared within them. The changes are then saved in the file HeatingCircuit_3Point.exp, and the text editor is closed. After this we can import the HeatingCircuit_3Point.exp file with installation identifier HC2.
By repeating this process, a large heat distributor with a large number of heating circuits can be programmed in a very short time.
Beckhoff Building Automation