ProSoft Technology MVI56-101S - Manual (Page 138)

Reference MVI56-101S ♦ ControlLogix Platform
User Manual IEC 60870-5-101 Slave Communication Module
Page 138 of 193 ProSoft Technology, Inc.
August 2, 2011
The Control Normalized Measured information objects use a data representation
defined by the protocol specification to represent fractional decimal values. The
following table describes the value for each bit as a reciprocal power of two (2),
that is two (2) raised to the power of a negative exponent (-1 through -15). Bit 15
is the Sign Bit.
Bit 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
Value
Hex(h)
Decimal
Sign
4000h
2
-1
2000h
2
-2
1000h
2
-3
800
h
2
-4
400
h
2
-5
200
h
2
-6
100
h
2
-7
80
h
2
-8
40
h
2
-9
20
h
2
-10
10
h
2
-11
8h
2
-12
4h
2
-13
2h
2
-14
1h
2
-15
4000h
0.5
0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0
2000h
0.25
0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0
1000h
0.125
0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0
6000h
0.75
0 1 1 0 0 0 0 0 0 0 0 0 0 0 0 0
3210h
0.395751953125
0 0 1 1 0 0 1 0 0 0 0 1 0 0 0 0
Examples:
A value of 4000hex (only Bit 14 set, all others clear) is interpreted as 0.5 decimal
A value of 2000hex (only Bit 13 set, all others clear) is interpreted as 0.25
decimal
A value of 1000hex (only Bit 12 set, all others clear) is interpreted as 0.125
decimal
... and so on until...
A value of 0001hex (Only Bit 0 set, all others clear) is interpreted as
0.000030517578125
Therefore, the actual data values transmitted may be any combination of the
decimal values for any given bit pattern.