Object Instance No. Allocation - Mitsubishi Heavy Industries SC-WBGW256 Configuration Manual

5 OBJECT INSTANCE NO. ALLOCATION

The BACnet standard defines the format of the BACnet Object Identifier as shown in the following diagram. That is,
the 32 bits of the BACnet Object Identifier consists of the higher 10 bits of the BACnet Object Type and the lower 22
bits of the Instance No.
31
BACnet Object Type
In this gateway, the 22 bits of the Instance No. shown above are divided into the higher 14 bits and the lower 8bits
as corresponding with the Air-con CELL No. and its Object Member No. as shown in the following diagram. This
structure comes from the concept that each Air-con CELL has a number of Object Members.
31
BACnet Object Type
For example, the Instance No. of the Mode command Object(Member No. is 5) of the Air-con CELL No.010 is to be
defined as follows.
Meaning
Bits of CELL & Member
Instance No. bit string
Calculation method
In the case of the System Stop command Object which is only one for this gateway, the Instance No. of the System
Stop command object is defined so as to be the Object Member No.21 of the Air-con CELL No.000.
22 21
Fig. 7 Format of the BACnet Object Identifier
22 21
Air-con CELL No.
Fig. 8 Format of the Instance No. in this gateway
Air-con CELL No.
CELL No. = 010
00000000001010
00000000001010 00000101 = X'0A05' = 2565
SC-WBGW256 Configuration Manual(BACnet) Ver.1.0
Instance No.
8 7
Object Member No.
Object Member No. = 5
00000101
10 x 256 + 5 = 2565
9
Document No. ISTZ17022 June 1, 2017
0
0
Object Member No.