Rosemount 3095FB - Page 54

Model 3095FB Multivariable Transmitter with Modbus Protocol
Modbus Protocol Guide
Page 23 of 79
3.4 Floating Point Formats (available for 3095FB output board software Rev. 107 or later)
The 3095FB has the capability to rearrange the transmission byte order of the floating point
registers. The floating point registers will still be in IEEE 754 format, only the transmission
byte order will change. Writing the Floating Point Format Code affects both the reading and
writing of the floating point registers. All the floating point registers in the transmitter are
affected by this register. The available Floating Point Formats are shown in Table 3-5. Chang-
ing the Floating Point Format Code will not affect the transmission byte order of the integer
data.
Table 3-3 Floating Point Format Code
Modbus Access
DESCRIPTION
Address
Address
Type
Attributes
Functional
Area
Data / Control
0132 Holding
register
RW, WP Communi-
cation
Floating Point Format Code
*Attributes: R/W = Read/Write, RO = Read Only, WP = Write Protected
**These registers are available at multiple Modbus addresses (see Section 2.3
located in the Modbus Protocol Guide)
Table 3-4 Floating Point Format
Byte Order
Notation A B C D
IEEE 754 Float-
ing Point Format
SEEE EEEE EMMM MMMM MMMM MMMM MMMM MMMM
Example Number
(100.25)
$42 $C8 $80 $00
Legend: S = sign bit; E= exponent bits; M = mantissa bits
Table 3-5 Available Floating Point Formats
Floating Point Format Code Byte Transmission Order Example Number (100.25)
0 (default) A B C D $42 C8 80 00
1 C D A B $80 00 42 C8
2 D C B A $00 80 C8 42
3 B A D C $C8 42 00 80