[HelloWorld21] Hello world, first example

Plant example HelloWorld21 has a variable speed fan, hot water heating coil and a shutoff damper. The example represents basic HVAC functions and displays the most important concepts of the plant application.

Functions

Supply air temperature control
Pressure control

Plant diagram

Components

Supply air fan, speed-controlled
Outside air shutoff damper
Hot water heating coil

Components and functions

Components and functions of the plant example:

Component	Function	BACnet object
	Fire detection contact Switches the plant off.	[BI] Fire detection contact
	Manual operating mode selection Switches the plant to: Auto \| Off \| On	[MCnfVal] Manual operating mode selection
	Maintenance switch Switches the plant to: Normal \| Maintenance	[BI] Maintenance switch
	Scheduler program Switches the plant to: Off \| On	[MSchedule] Scheduler
	Present operating mode Reports the present operating mode: Off \| On Plant operating modes and control sequence	[MCalcVal] Present operating mode
	Supply air temperature setpoint	[AcnfVal] Setpoint for supply air temperature
	Supply air differential pressure sensor Measures the differential pressure between duct and environment.	[AI] Supply air pressure (Located in Supply air fan)
	Supply air temperature sensor Measures the supply air temperature.	[AI] Supply air temperature
	Heating coil	Heating coil (Folder)
	Reports hot water demand to heat distribution.	> [BCalcVal] Hot water demand
	Frost protection Prevents the hot water heating coil from freezing. If the frost protection monitor triggers: The plant switches off. The valve fully opens (100%) and the pump is also switched on. Both at high priority (Prio 4).	> [BI] Frost protection monitor
	Pump	Pump (Folder)
	Pump command Switches on/off the pump as needed.	> [BO] Command
	Valve	Valve (Folder)
	Temperature controller Controls the supply air temperature. Function diagram for supply air temperature control	> [Controller] Temperature controller
	Valve position Controls the valve position: 0…100 [%]	> [AO] Position
	Supply air fan	Supply air fan (Folder)
	Pressure controller Controls the supply air pressure. Function diagram for supply air pressure control	> [Controller] Pressure controller
	Determines the setpoint for supply air pressure.	> [ACnfVal] Setpoint supply air pressure
	Command Switches on/off the fan as needed.	> [BI] Command
	Speed Controls the fan speed between 0 and 100 [%].	> [AO] Speed
	Maintenance switch Switches off the fan and the plant. The fan outputs are blocked locally at a high priority (Prio 2).	> [BI] Maintenance switch
	Outside air damper	Outside air damper (Folder)
	Command Opens and closes the outside air damper.	> [BO] Command

Functions and diagrams

Temperature control

Supply air temperature control – Heating coil valve position

Key

Vlv-Pos	Valve position
Hcl'Vlv'Pos	Heating coil valve position
SpTSu	Setpoint for supply air temperature
TSu	Supply air temperature

BACnet objects

Name	Description	Object type	Default value
Hcl'Vlv'TCtr	Temperature controller for heating coil Controls the supply air temperature.	Controller	N/A
The temperature controller acts as a PI controller (PID with derivative action time Tv=0) and compares the temperature setpoint [SpTSu] against the supply air temperature [TSu] and calculates the valve position [Hcl'Vlv'Pos] on the output. The following controller variables are preset: - Controller gain: 5 [%/K] - Integral action time Tn: 180 [s]

Name

Description

Object type

Default value

Hcl'Vlv'TCtr

Temperature controller for heating coil

Controls the supply air temperature.

Controller

N/A

The temperature controller acts as a PI controller (PID with derivative action time Tv=0) and compares the temperature setpoint [SpTSu] against the supply air temperature [TSu] and calculates the valve position [Hcl'Vlv'Pos] on the output.

The following controller variables are preset:
- Controller gain: 5 [%/K]
- Integral action time Tn: 180 [s]

Heating coil valve control - Heating coil pump command

Key

Hcl'Pu'Cmd	Heating coil pump command
Hcl'Vlv'Pos	Heating coil valve position

Supply air pressure control - Fan speed

Key

FanSu'Spd	Supply air fan speed
SpPSu	Setpoint supply air pressure
PSu	Supply air pressure

BACnet objects

Name	Description	Object type	Default value
FanSu'PCtr	Pressure controller for supply air fan Controls the supply air pressure.	Controller	N/A
The pressure controller acts as a PI controller (PID with derivative action time Tv=0) and compares the setpoint for supply air pressure [SpPSu] against the supply air pressure [PSu] and calculates the fan speed [Spd] on the output. The following controller variables are preset: - Controller gain: 0.2 [%/Pa] - Integral action time Tn: 60 [s]

Name

Description

Object type

Default value

FanSu'PCtr

Pressure controller for supply air fan

Controls the supply air pressure.

Controller

N/A

The pressure controller acts as a PI controller (PID with derivative action time Tv=0) and compares the setpoint for supply air pressure [SpPSu] against the supply air pressure [PSu] and calculates the fan speed [Spd] on the output.

The following controller variables are preset:
- Controller gain: 0.2 [%/Pa]
- Integral action time Tn: 60 [s]

Plant operating modes and control sequence

Plant operating modes:

Off (1)
On (2)

The operating modes are reported on [MCalcVal] object 'Present operating mode'.

The components for control are connected to function block CMDSEQ_B and are also acquired by this function block. See table below.
[CMDSEQ_B] Command sequence for binary

There is a normal mode and exception mode.

Normal operation

Sources for normal mode:

[MCnfVal] Manual operating mode selection
[MSchedule] Scheduler

In normal mode, the components are controlled at priority 15 per the operating mode, sequence, and function in function block CMDSEQ_B. The set timeouts and/or delays are considered.

Exception mode

Sources for exception mode:

Fire detection contact
Faults in the components frost protection monitor and maintenance switch

In exception mode, all outputs are switched off directly at priority 5 and the present operating mode is set to 'Off'. This is reported to function block CMDSEQ_B on input [RpdOff] and the components are switched off immediately as of the function block at priority 15.

The set timeouts and/or delays are not considered.

Special case frost protection:

In this case, outputs [AO] valve position and [BO] pump command are switched on by the heating coil at priority 4.

Special case maintenance switch:

In this case, outputs [AO] speed and [BO] command are switched off by the fans at priority 2.

Components, sequence, and function in CMDSEQ_B

Plant operating mode	Component
	Hcl	DmpOa	FanSu
Off	Off	Off	Off
On	On	On	On

Sequences
Start sequence	1	2	3
Start function	Delay	Delay	AND (Group with next aggregate)
Start delay	10s	15s	-

Stop sequence	2	2	1
Stop function	AND (Group with next aggregate)	AND (Group with next aggregate)	Delay
Stop delay	-	-	10s

Start sequence

The heating coil switches on. Switched after 10 seconds.
The shutoff damper opens. Switched after 15 seconds.
The supply air fan switches on.

Stop sequence

The supply air fan switches off. It waits for 10 seconds (function delay).
The shutoff damper closes and the cooling coil switches off (function AND).

I/O data points

Name	Description	Type	Signal/connection	State text	Engineering unit
FireDetCont	Fire detection contact Alarm function: Extended (Notification class 7) Reference value: Tripped Time deviation: 0 [s]	BI	NC contact	Normal \| Tripped	N/A
FanSu'PSu	Supply air fan supply air pressure	AI	0...10 [V]	N/A	0...500 [Pa]
TSu	Supply air temperature	AI	LG-Ni1000	N/A	0...50 [°C]
Hcl'Vlv'Pos	Heating coil valve position	AO	0...10 [V]	N/A	0...100 [%]
Hcl'Pu'Cmd	Heating coil pump command	BO	NO contact	Off \| On	N/A
Hcl'FrPrtMon	Heating coil frost protection monitor Alarm function: Extended (Notification class 7) Reference value: Tripped Time deviation: 0 [s]	BI	NC contact	Normal \| Tripped	N/A
FanSu'Spd	Supply air fan speed	AO	0...10 [V]	N/A	0...100 [%]
FanSu'Cmd	Supply air fan command	BO	NO contact	Off \| On	N/A
FanSu'MntnSwi	Supply air fan maintenance switch Alarm function: Basic (Notification class 8) Reference value: Maintenance Time deviation: 0 [s]	BI	NO contact	Normal \| Maintenance	N/A
DmpOa'Cmd	Outside air damper command	BO	NO contact	Close \| Open	N/A