Supplement operating manual for DREHMO i-Matic actuators with integrated
MODBUS fieldbus interface
Wenden, 21.03.12
Page 9 of 18
Prepared by: Ste
database address (decimal 512)
function code 06 write single register (commands as integer)
slave address 200 in example
The actuator commands can also be read back for checking purposes with the function codes FC 01 (Read
Coil Status) or FC 03 (Read Holding Registers). The following tables give telegram examples for these
function codes.
telegram example FC01 read single bit of master output data (command check)
Request
C8 01 00 00 00 80 2C 33
Checksum
number coils (discrete command bits - 128)
database address (decimal 0)
function code 01 read coil status (command check)
slave address 200 in example
Response
C8 01 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 A6 6D
Checksum
discrete coil (command
check) information (0) -
lowbyte-highbyte order
number of databytes
function code 01 read coil
status (command check)
slave address 200 in
example
telegram example FC03 read back of master output as integer (command check)
request
C8 03 02 00 00 08 54 2D
Checksum
number of data (commands packed as integer - 8)
database address (decimal 512)
function code 03 read holding register (command check as integer)
slave address 200 in example
Response
C8 03 10 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 07 D5
Checksum
holding register values
(command check as integer,
highbyte-lowbyte order)
number of databytes
function code 03 read holding
register (command check)
slave address 200 in
example
It is important to pay attention to the fact that the address count in the telegrams is starting at zero
and the coil and register address counts are starting at one, thus resulting in an address offset of
one!
