ABB ControlIT 53MC5000 Instruction Manual page 345

B.1.5 CALCULATING DATA ADDRESSES
If communications software must be generated to accommodate unique Datalink applications re-
quirements, then the controller memory address scheme must be known for proper data bit (e.g., L
data type) and data byte (e.g., B, C, H, and A data types) memory location determination.
Note: Numbers used in this section that are expressed in hexadecimal notation (base 16) are iden-
tified with a subscript
H
This memory address scheme applies only if a 6 is in memory address location 8002
address location 8002
H
scribed in Table B-3 should be applied for this controller.
Table B-3. Controller Memory Address Scheme
Data Base Byte
Type Memory Size
Address
B 200 1
H
L 500 1 Bit
H
C 600 3
H
B-6
53MC5000 Process Control Station
after the number.
must be read and if it contains a 6 , then the address scheme that is de-
Data Format
Represents a positive integer
with values from 0 to 255.
A single binary bit with a logical
value of 0 or 1. L datapoints
are packed 8 to a byte.
Represents floating point values
that have a resolution of one
part in 32,768 (15 bits) and a
dynamic range of ± 10
first two bytes represent a 2's
complement notation in
-n
fractional form (2
absolute value is between 0.5
and 0.9999. The third byte is
the power of 2 in 2's
complement notation. Floating
point example:
64 00 07 = 100
H H H
64 = 0110 0100, fractional
H
binary weights left to right are 0
= 2's complement positive,
-1
1 = 2 = 1/2 = 0.5, 1 = 2
1/4 = 0.25, 0=0, 0=0, 1 = 2
1/32 = 0.03125, 0=0, and 0=0.
64 = 0.5+0.25+0.03125 =
H
0.78125. 07 = 128
H
0.78125 = 100.
D
Address Calculation Algorithm
Address = B Base + (B Number)
Address example: B012 location
= 200 + 12
H
Address = L Base + (L Number/8)
Remainder = bit position in byte
Address example: L014 location
= 500 + 14/8 = 501
H
(remainder).
Address = C Base + (3 X C Number)
Address example: C011 location
38
. The 600 + (3 X 11) = 600
H
= 600 + 21
H
) whose
(Decimal)
D
-2
=
-5
=
. 128 X
D D
. Memory
H
1 of 2
= 200 + (B Number)
H
= 200 + C = 20C
D H H
= 500 + (L Number/8)
H
, bit 6
H
= 600 + (3 X C Number)
H
+ 33
H D
= 621 .
H H
H