Command

Several control or positioning commands of an object to be commanded have an influence on the output value PresentValue. All commands are stored in an array. The command with the highest priority determines the result at the output of the object.

A priority can be given a value between 1 and 16. The highest priority has the value 1.

The following objects in TwinCAT 3 Building Automation are objects to be commanded and thus have a priority array.

FB	Type	Description
FB_BA_BO_Raw	BO	Binary output with external declaration of variables for hardware mapping.
FB_BA_BO	BO	Binary.
FB_BA_BO_IO	BO	Binary output with internal declaration of variables for hardware mapping.
FB_BA_AO_Raw	AO	Analog output with external declaration of variables for hardware mapping.
FB_BA_AO	AO	Analog.
FB_BA_AO_IO	AO	Analog output with internal declaration of variables for hardware mapping.
FB_BA_MO_Raw	MO	Multi State output with external declaration of the variables for hardware mapping.
FB_BA_MO	MO	Multi State output.
FB_BA_MO_IO	MO	Multi State output with internal declaration of variables for hardware mapping.
FB_BA_BV	BV	Binary Value object.
FB_BA_MV	MV	Multistate Value object.
FB_BA_AV	AV	Analog Value object.

For an entry to be made in the priority array of an object, the associated enable input bEn... must be TRUE on the function block.

The Manual Remote priority is not activated by means of an input at the function block, but by writing to a parameter variable. The object is commanded either via the BACnet protocol, e.g. from an MBE, or from TwinCAT via ADS.

The following priorities are predefined at the objects by TwinCAT Building Automation:

Name	Description	Symbol release	Symbol value	Default Prio
Safety	Personal safety	bEnSafety	*ValSfty	1
Critical	Plant safety	bEnCrit	*ValCritical	3
ManLoc	Local manual override (LVB)	bEnManLoc	*ValManLoc	7
ManualRm	Manual override from a distance (MBE)	bEnManualRm	*ValManualRm	8
Pgm	Program control	bEnPgm	*ValPgm	15

Depending on whether the object type is Analog, Binary or Multi State, the value of a command is a REAL, BOOL or UDINT.

Changing priorities

The priorities can be changed in the variable list BA_BACnet_Param.

The active priority is displayed at the output of all objects to be commanded by means of the variable eActivePrio.

Variables

Name	Type	Description
bEnSafety	BOOL	Enabling the "Safety" priority.
fValSafety	REAL	Analog value for the "Safety" priority.
bValSafety	BOOL	Binary value for the "Safety" priority.
nValSafety	INT	Integer value for the "Safety" priority.
bEnCritical	BOOL	Enabling the "Critical" priority.
fValCritical	REAL	Analog value for the "Critical" priority.
bValCritical	BOOL	Binary value for the "Critical" priority.
nManCritical	INT	Integer value for the "Critical" priority.
bEnManLocal	BOOL	Enabling the "Manual Local" priority.
fValManLocal	REAL	Analog value for the "Manual Local" priority.
bValManLocal	BOOL	Binary value for the "Manual Local" priority.
nManLocal	INT	Integer value for the "Manual Local" priority.
bEnManualRm	BOOL	Enabling the "Manual Remote" priority.
fValManualRm	REAL	Analog value for the "Manual Remote" priority.
bValManualRm	BOOL	Binary value for the "Manual Remote" priority.
nManualRm	INT	Integer value for the "Manual Remote" priority.
bEnPgm	BOOL	Enabling the "Program" priority.
fValPgm	REAL	Analog value for the "Program" priority.
bValPgm	BOOL	Binary value for the "Program" priority.
nPgm	INT	Integer value for the "Program" priority.