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Rockwell Automation Publication IOLINK-UM001A-EN-P - August 2017
Appendix B
Message Structure and Configuration Examples
Service Code
Table 2
is used to determine the Service Code that is needed for a specific
Message Instruction.
Table 2 - Service Code
Source Length: from Data Structure Tables
The following tables can be used to determine the source length that is based
on the Service Code that is used and the number of bytes being written.
Table 3 - Read Subindex (4B) - Message Data Format
Source Length= 2 bytes
Table 4 - Read Subindex (4C) - Message Data Format
Source Length= 2 bytes + Number of bytes of data being written
Table 5 - Read Subindex (4D) - Message Data Format
Source Length= 1 byte
Table 6 - Write Index (4E) - Message Data Format
Source Length= 1 byte + Number of bytes of data being written
Service Code (Hex)
Need in Implementation
Service Name
Description of Service
Class
Instance
4B
Required
Required
Read Subindex
Reads a parameter value from the IO-Link device
4C
—
Required
Write Subindex
Writes a parameter value from the IO-Link device
4D
Required
Required
Read Subindex
Reads an entire index (all parameters within an index) from the IO-Link
device (uses subindex 0)
4E
—
Required
Write Subindex
Writes an entire index (all parameters within an index) from the IO-Link
device (uses subindex 0)
Byte 0
Byte 1
Subindex Number
Channel Number
Byte 0
Byte 1
Byte 2
Byte 3
Subindex Number
Channel Number
Data 0
Data 1
Byte 0
Channel Number = 1 byte
Byte 0
Byte 1
Byte 2
Byte 3
Channel Number
Data 0
Data 1
Data 3
Summary of Contents for Allen-Bradley 836P Series
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