Micromod Micro-DCI: 53ML5100A LOADING STATION REV. 1 FIRMWARE - Manual (Page 15)

53ML5100A Manual Loading Station
Supplement to the Instruction Bulletin
Datalink Communications 11
4.2 CALCULATING DATA ADDRESSES
If communications software must be generated to accommodate unique Datalink applications require-
ments, then the instrument memory address scheme must be known for proper data bit (e.g., L datapoints)
and data byte (e.g., B, C, H, and A datapoints) memory location determination.
This memory address scheme applies only if a 6 is in memory address location 8002
H
. Memory address
location 8002
H
must be read and if it contains a 6, then the address scheme that is described in Table 4-2
should be applied for this instrument.
✎ Note
Hexadecimal (base 16) numbers used in this section are identified
with a subscript
H
after the number.
Table 4-2. Controller Memory Address Scheme
Data
Type
Base
Memory
Address
Byte
Size
Data Format Address Calculation Algorithm
B 200
H
1 Represents a positive integer with values
from 0 to 255. Address = B Base + (B Number)
= 200
H
+ (B Number)
Address example: B012 location
= 200
H
+ 12
D
= 200
H
+ C
H
= 20C
H
L 500
H
1 Bit A single binary bit with a logical value of 0
or 1. L datapoints are packed 8 to a byte. Address = L Base + (L Number/8)
= 500
H
+ (L Number/8)
Remainder = bit position in byte
Address example: L014 location
= 500
H
+ 14/8 = 501
H
, bit 6
(remainder).
C 600
H
3 Represents floating point values that have
a resolution of one part in 32,768 (15 bits)
and a dynamic range of ± 10
38
.
The first two bytes represent a 2’s
complement notation in fractional form (2
-
n
) whose 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
H
00
H
07
H
= 100
D
(Decimal)
64
H
= 0110 0100, fractional binary weights
left to right are 0 = 2’s complement
positive,
1 = 2
-1
= 1/2 = 0.5, 1 = 2
-2
= 1/4 = 0.25,
0=0, 0=0, 1 = 2
-5
= 1/32 = 0.03125, 0=0,
and 0=0.
64
H
= 0.5+0.25+0.03125 = 0.78125.07
H
=
128
D
. 128
D
X 0.78125
D
= 100.
Address = C Base + (3 X C Number)
= 600
H
+ (3 X C Number)
Address example: C011 location
600
H
+ (3 X 11) = 600
H
+ 33
D
= 600
H
+ 21
H
= 621
H
.