ProSoft Technology 5201-DFNT-BACNET User Manual
Page 31
BACnet ♦ ProLinx Gateway
BACnet Protocol Configuration
BACnet/IP Client Edition 2
Protocol Manual
ProSoft Technology, Inc.
Page 31 of 52
November 24, 2010
Property
Code
Description
Length
Data Type
AI
AO
BI
BO
46
Inactive Text
Character String
O
O
4
Active Text
Character String
O
O
15
Change of State Count
Unsigned
O
O
33
Elapsed Active Time
Unsigned32
O
O
6
Alarm Value
Byte (Enumerated)
O
66
Minimum Off Time
Unsigned32
O
67
Minimum On Time
Unsigned32
O
40
Feedback Value
Byte (Enumerated)
O
R=Read-only required by all devices.
W=Read/Write required by all devices.
O=Read-only and is optional for device.
If cell is blank, the property is not supported for the data type.
Please review the BACnet Protocol Specification for a complete discussion of
each of the property identification codes and for the definition of the enumerated
values. Care must be taken when designing the application to make sure
command message data does not overlap. Consult the server device
documentation to verify that the data type, point number, function and property
identification code are supported.
The Property ID column determines the Internal Address field. Use the previously
provided Property ID table to determine the data type used with the point.
Data Length
Internal Address Offset
Bit
Bit offset from start of database (packed data) (0 to 64000) - Each data point uses a single bit in
the database.
Byte
Byte offset from start of database (0 to 7999) - Each data point uses a single byte in the database.
Unsigned
(Byte offset)*2 from start of database (0 to 3999) - Each data point uses two bytes (one word
register) in the database.
Unsigned32
(Byte offset)*4 from start of database (0 to 2999) - Each data point uses four bytes (two word
registers) in the database.
4-Bytes
(Byte offset)*4 from start of database (0 to 2999) - Each data point uses four bytes (two word
registers) in the database.
4-Byte Real
(Byte offset)*4 from start of database (0 to 2999) - Each data point uses four bytes (two word
registers) in the database.
Character String
Byte offset from start of database (0 to 7999) - Each data point uses the number of bytes required
to store the character string. Care should be used with these property types to make sure the
database of one point does not overlap that of another.
NOTES
The length of the Character String type is variable and may cause for a read operation to
overwrite other data if not enough space is allocated for each string.
The binary input present value (property 85) returned from a read statement is placed at the bit
offset in the internal address.
The bit offset in the internal database is used for the binary output read and write operations.