Watlow CLS200, MLS300 and CAS200 - Manual (Page 38)

32 Communications Specification
Chapter 2: Modbus-RTU Protocol
Write Examples
The data written is echoed back to the controller.
Sample Packet for Host Transmission, a Single-Point Write
Sample Packet for Slave Transmission, a Single-Point Write
Example
Slave
Address
in Hex
Function
in Hex
Address
High
in Hex
Address
Low
in Hex
Data
High
in Hex
Data
Low
in Hex
CRC
High
in Hex
CRC
Low
in Hex
4. Writing loop 1
gain (20),
controller 4
(single-point
write) 04 06 00 00 00 14 89 90
5. Writing
digital output 30
(on), controller 2
(single coil
write) 02 05 03 A8 FF 00 0D AD
Example
Slave
Address
in Hex
Function
in Hex
Address
High
in Hex
Address
Low
in Hex
Data
High
in Hex
Data
Low
in Hex
CRC
High
in Hex
CRC
Low
in Hex
4. Writing loop 1
gain (20),
controller 4
(single-point
write) 04 06 00 00 00 14 89 90
5. Writing
digital output 30
(on), controller 2
(single coil
write) 02 05 03 A8 FF 00 OD AD