Rockwell Automation 900 Temperature Controller Communications Functions - Series B - Manual (Page 66)

Publication 900-UM004D-EN-E - July 2010
4-8 Modbus Communications Procedure
Example: D’105.0
→
H’0000041A
The variables are 4- or 8-digit hexadecimal values. Negative values are
expressed in 2’s complement format. The values are hexadecimal values with
no decimal point indication.
For example, if the 900-TC8 , 900-TC16, or 900-TC32’s process value is read
in 4-byte mode when the process value is 105.0, the read value will be
H'0000041A (105.0 → 1050 → H'0000041A).
Detailed Description of the
Services Read Variable Area
To read from the variable area, set the required data in the command frame, as
shown in Figure 4.7.
Figure 4.7 Command Frame
CRC-16
1 1
H'03
2 2
Number of
Elements
2 bytes
Slave
address
Function
code
Read
start address