Siemens SIMATIC PN/BACnet LINK - Page 39

Functions
4.5 Acyclic data exchange
PN/BACnet LINK
Operating Instructions, 10/2017, A5E39895543-AA
39
ReadProperty
For a "ReadProperty", the data record must contain the corresponding parameters for the
service. The result is located in a data record, which must then be read.
Table 4- 5 WRREC (write data record) - data record structure for "ReadProperty" service
Element
Type
Meaning
PNreq
UINT8
PROFINET service: Property access = 1
BNreq
UINT8
BACnet service: "ReadProperty" = 0x0C = 12
DNET
UINT32
Network number
Device ID UINT32 BACnet device instance number
ObjectID
UINT32
BACnet ObjectID (type and instance)
PropertyID
UINT32
PropertyID
ArrayIndex
INT32
Property index (-1 = no index)
Table 4- 6 RDREC (record read) - data record structure for "ReadProperty" result
Element
Type
Meaning
PNresp
UINT8
PROFINET error number (0 == no error)
BNresp
UINT8
BACnet error number (0 == no error)
DNET/ErrorClass
UINT32
Network number (BNresp == 0)/BACnet error class (BNresp != 0)
Device/ErrorCode UINT32 BACnet device instance (BNresp == 0)/BACnet error code
(BNresp != 0)
ObjectID
UINT32
BACnet ObjectID (type and instance)
PropertyID
UINT32
PropertyID
ArrayIndex
INT32
Property index (-1 = no index)
empty1
UINT16
Not assigned
empty2
UINT16
Not assigned
Len
UINT16
Length of value in bytes
Value
Array
BACnet property value in ASN.1 format (BNresp == 0)