Siemens SENTRON ATC6300 - MODBUS Functions

MODBUS communication
11.4 MODBUS functions
3KC ATC6300 transfer control device
Manual, 03/2018, L1V30535632002A-01
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11.4
MODBUS functions
The following MODBUS functions can be performed with the ATC6300:
03 = Read input register
Allows parameters of the ATC to be read.
04 = Read input register
Allows parameters of the ATC to be read.
06 = Preset single register Allows parameters of the ATC to be rewritten.
07 = Read execption
Allows the status of the ATC to be viewed.
10 = Preset multiple register Allows some parameters of the ATC to be rewrit-
ten.
17 = Report slave ID
Allows information about the ATC to be read out.
Function 04: Read input register
The MODBUS function 04 permits the reading of one or more consecutive registers from a
memory of the slave.
The register addresses are contained under the subsection Data library (Page 157). As in
the case of MODBUS as standard, the effective register address from the data library must
also be reduced by the factor 1 in the case of queries. If the register address is not contained
in data library 11.5, or the number of registers specified exceeds the accepted number, an
error message is displayed in accordance with the section "Error Messages".
Querying of the master:
Slave address
08h
Function
04h
MSB address
00h
LSB address
0Fh
MSB register number
00h
LSB register number
08h
LSB CRC
C1h
MSB CRC
56h
In the previous example, 8 consecutive registers are requested by the slave. Starting with
register 10h, the registers 10h to 17h are output. The message is concluded by the CRC
Checksum .