2 function code 05h – execute operation – GE Industrial Solutions Entellisys 5.0 Integrator's Guide User Manual
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Modbus® protocol implementation
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3.5.2 Function Code 05H – Execute Operation
This function code allows the master to perform various operations in the CPU.
The following table shows the format of the master and slave packets. The example shows a
master device requesting the slave device 11H (17 dec) to perform a reset. The hi and lo CODE
VALUE bytes always have the values ‘FF’ and ‘00’ respectively and are a remnant of the original
Modbus definition of this function code.
Master and Slave Device Packet Transmission Example
MASTER TRANSMISSION
PACKET FORMAT
EXAMPLE (HEX)
SLAVE ADDRESS
11
FUNCTION CODE
05
OPERATION CODE - hi
00
OPERATION CODE - lo
01
CODE VALUE - hi
FF
CODE VALUE - lo
00
CRC - lo
DF
CRC - hi
6A
SLAVE RESPONSE
PACKET FORMAT
EXAMPLE (HEX)
SLAVE ADDRESS
11
FUNCTION CODE
05
OPERATION CODE - hi
00
OPERATION CODE - lo
01
CODE VALUE - hi
FF
CODE VALUE - lo
00
CRC - lo
DF
CRC - hi
6A