![background image](http://html1.mh-extra.com/html/eaton/iq-250/iq-250_user-and-installation-manual_3836163106.webp)
Appendix B:
Modbus Mapping for IQ 250/260 IQ 250/260 Meter
B-2
IB02601006E
www.eaton.com
Floating Point Values
Floating Point Values are represented in the following format:
Register
0 1
Byte
0 1
0
1
Bit
7 6 5 4 3 2 1 0 7 6
5 4 3 2
1 0
7 6 5
4
3 2
1 0 7 6 5 4
3
2
1
0
Meaning
s
e e e e e e e e m m m
m
m m m m m m m m m m m m m m m m m m m
sign
exponent mantissa
The formula to interpret a Floating Point Value is: -1
sign
x 2
exponent-127
x1.mantissa = 0x0C4E11DB9
-1
sign
x 2
137-127
x 1
·
1000010001110110111001
-1 x 2
10
x 1.75871956
-1800.929
Formula Explanation:
C4E11DB9 (hex)
11000100 11100001 00011101 10111001 (binary)
The sign of the mantissa (and therefore the number) is 1, which represents a negative
value.
The Exponent is 10001001 (binary) or 137 decimal.
The Exponent is a value in excess 127. So, the Exponent value is 10.
The Mantissa is 11000010001110110111001 binary.
With the implied leading 1, the Mantissa is (1).C23B72 (hex).
The Floating Point Representation is therefore -1.75871956 times 2 to the 10.
Decimal equivalent: -1800.929
NOTES:
• Exponent = the whole number before the decimal point.
• Mantissa = the positive fraction after the decimal point.
Modbus Register Map (MM-1 to MM-22)
The IQ 250/260 Modbus Register Map begins on the following page.
Register
0x0C4E1 0x01DB9
Byte
0x0C4 0x0E1
0x01D
0x0B9
Bit
7
6 5 4 3 2 1 0 7
6 5
4 3
2 1
0 7
6
5
4 3
2
1 0 7 6 5 4 3
2 1
0
1
1 0 0 0 1 0 0 1
1 1
0 0
0 0
1 0
0
0
1 1
1
0 1 1 0 1 1 1
0 0
1
Meaning
s
e e e e e e e e m
m m
m m
m m
m m m m m m m m m m m m
m m
m m
sign exponent
mantissa
1
0x089 + 137
0b011000010001110110111001
Summary of Contents for IQ 250
Page 2: ......
Page 22: ...3 6 IB02601006E www eaton com Chapter 3 Mechanical Installation IQ 250 260 Meter...
Page 38: ...4 16 IB2601006E www eaton com Chapter 4 Electrical Installation IQ 250 260 Meter...
Page 104: ...A 6 IB02601006E www eaton com Appendix A IQ 250 260 Navigation Maps IQ 250 260 Meter...
Page 134: ...A IQ 250 260 Meter Appendix B Modbus Mapping www eaton com IB02601006E MM 28...