IFM AL1340 - Page 73

IO-Link Master with Modbus TCP Interface DataLine 4 Ports IP 65 / IP 66 / IP 67
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9.3.12 Modbus TCP: Programmers' notes
Content
Rules for accessing the Modbus registers .............................................................................................73
Supported function codes .......................................................................................................................73
Note: Exception Codes ...........................................................................................................................74
Use acyclic services ...............................................................................................................................75
33665
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Rules for accessing the Modbus registers
54703
The following general rules apply for access to the Modbus registers:
► Only use the valid function codes to read or write Modbus registers (→ Supported function
codes (→ S. 73)).
► After every read or write access check the validity of the transmitted data (→ Mapping: PQI
(→ S. 99)).
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Supported function codes
34440
The AL1340 supports the following function codes for read and/or write access to the Modbus register:
Function code
Function name / description
03 (0x03)
Read Multiple Registers
04 (0x04)
Read Input Register
06 (0x06)
Write Single Register
16 (0x10)
Write Multiple Registers
23 (0x17)
Read/Write Multiple Registers
43 (0x2B)
Read Device Identification
Detailed information about the function codes: → MODBUS-TCP specification