Michell Instruments Promet EExd User Manual page 67

Promet EExd User's Manual
The table below shows the data bytes in a
to 4 contain the address of the Promet EExd, Modbus function, starting register address
and the data value to be written. In this example a master sends FC18H to address
0015H, to a Promet EExd with an address of 01H. The CRC is calculated using the data
in bytes 1 to 6.
Byte No
Write Single Register Request and Response
The normal response from the Promet EExd is to re-transmit the received message.
However, if the data within the message is incorrect then an exception response will be
transmitted.
Michell Instruments
1 Slave Address
2 MODBUS function code
3 Starting Address MSB
4 Starting Address LSB
5
6
7
8
Write To Single Register
Meaning
Data MSB
Data LSB
CRC Lo Byte
CRC Hi Byte
APPENDIX E
message. Bytes 1
Value
01H
06H
00H
15H
FCH
18H
??H
??H
59