Annexes
ABB Control - AC 31 Annexes - Page 9
1SBC 260400 R1001-b 06.99
3. Mapping
This paragraph describes the correspondence between the variables and their physical
memory addresses. This information is necessary for certain functions such as COPY, data
exchange between CS 31 bus master and slave central units.
The variable address is given by the segment and offset value.
These values are expressed in hexadecimal and decimal formats.
H0000 is the segment for all variables.
The correspondence between the variable and the offset is given in the following table:
8 bits used 1 byte – 1 word used 2 bytes.
Mapping addressing method:
VAR 00.00 ADDR 0
1- Bits: (VAR = type I,O,S,M,) (Address of the first selected variable in decimal)
VAR XX.YY = ADDR 0 + ( XX * 2 )
Warning: for variable type M, you have two area and you have to use M 000.00 = ADDR 0 for
the first area, and M 230.00 = ADDR 0 for the second area.
2- Words: (VAR = type IW,OW,KW,MW,) (Address of the first selected variable
in decimal)
VAR XX.YY = ADDR 0 + ( XX * 32 ) + ( YY * 2 )
Warning: for variable type KW the ADDR 0 is 28672 and for variable type MW, you have two
area and you have to use MW 000.00 = ADDR 0 for the first area, and MW 230.00 = ADDR 0
for the second area.
3- Double words: (VAR = type MD,KD) (Address of the first selected variable in decimal)
VAR XX.YY = ADDR 0 + ( XX * 64 ) + ( YY * 4 )
Example : Find the mapping
address of variables O 62.00 and OW 62.15, MW 240,15 and
MD002.07
O 62.00 = 6912 + ( 62 * 2 ) =
7036
OW 62.15 = 18432 + ( 62 * 32 ) + ( 15 * 2 ) = 11905
MW 240.15 = 10368 + ( 10 * 32 ) + ( 15 * 2 ) = 10718
MD 002.07 = 15872 + ( 2 * 64 ) + ( 7 * 4 ) = 16028
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