Emerson Rosemount 5708, Reference Manual

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Connection via RS-485
November 2017
Reference Manual
00809-0100-4570, Rev DA
Connection via RS-485
163
Each of the 4-byte blocks represents a floating point value according to the IEEE-754 standard. For more
information about the standard, refer to the following web page:
http://standards.ieee.org/findstds/standard/754-1985.html.
Example
Suppose the reply starts as follows (in this example, we show only the first 4 bytes of payload):
Then the average distance is represented by a 4-byte-block of 0x3D851E20 which corresponds to the
floating point value of 0.065m.
1. To verify the value, enter “3d851e20” in the hexadecimal representation text box at the
http://babbage.cs.qc.cuny.edu/IEEE-754/index.xhtml web page.
2. To calculate CRC-16, use the http://www.lammertbies.nl/comm/info/crc-calculation.html web site.
3. Select input type HEX .
4. Type in the string to convert and select the Calculate CRC button.
5. Look for the CRC-16 (Modbus) value in the table.
The output result is flipped. For example, if the result is 0x01C4, the two bytes to be transmitted are
C401.
Byte number Value
00 01
01 03
02 34
03 3D
04 85
05 1E
06 20
... ...