FloBoss™ S600+ Flow Computer Modbus Specification Manual
D301904X012
June 2024
13
Address Function
16-bit item
count Data Checksum
01 03 01 00 00 01 00 02 … up to 256
items
xx
Section 8. Register Formats
The Modicon Modbus Protocol Reference Guide (publication PI-MBUS-300, Rev. J, from
Modicon, Inc.) does not specify how numbers greater than 16 bits (that is, 32-bit integers
and single- and double-precision real numbers) should be transferred.
The Modbus protocol has 16-bit elements (“registers”) that are only suitable for
transferring 16-bit integer data. Since no standard exists, Emerson has developed the
following formats to transfer numerical data to and from third-party systems.
Float
Rosemount
Double
Phillips Float
Phillips Double
Enron 16-bit
Enron 32-bit
Enron Float
Scale 0 nnnn
Each of these formats is described in this section.
8.1 Single-Precision Floating Point: MSB First
[FORMAT FLOAT]
[FORMAT ENRON FLOAT]
[FORMAT PHILLIPS FLOAT]
Formats numerical items as IEEE format single-precision 32-bit floating point numbers,
with a standard “MSB first” byte order.
Four (4) bytes are used to represent the item, with the bytes being distributed across
register addresses according to the Addr/Item selection (A = MSB, etc.):