F_BACnet_RealPV : DWORD

Application

Function for implementing a REAL value of the PLC in the process data value of a BACnet analog* object property Present_Value. Using this function it is possible to write BACnet analog* objects, for example, which are only linked to a BACnet object via a primitive PLC variable (e.g.

rAV0 AT%Q* : DWORD; (* ~(BACnet_ObjectType : AV : NOLINK)(BACnet_ObjectIdentifier : 0 : NOLINK)(BACnet_PresentValue_Priority12 : : LINK) *)

).

The process data type DWORD must be used in the case of BACnet analog* objects, since special formats of the REAL data type are also used for encoding the property Present_Value. Depending on the target platform, process data of type REAL may not be treated properly, if special formats of the floating-point unit are used. The mapping of the process data between DWORD and REAL type is not critical, since the memory requirement is identical (4 bytes each).

VAR_INPUT

bEnable  : BOOL;
bNull    : BOOL;
rValue   : REAL;

bEnable: TRUE = The process data is enabled; the value resulting from bNull or rValue is written to the corresponding BACnet object, FALSE = process data is disabled

bNull: TRUE = zero writing of the BACnet object (e.g. for deleting a priority), FALSE = write value from rValue

rValue: Value that is written to the BACnet Object.