CANopen/SIIS2 – Part 3, SDO Index Map

SDO is the simplest part of CANopen that can be compared to Modbus. A SDO message is addressed to a node and consist of Index, Sub-index and 1-4 byte variable. A common implementation is to have indexes in an array with pointers to the actual variable and use bsearch to find index/sub-index. How you implement this is not part of the standard, so you could just implement a very large switch etc, but a table is recommended.

In fact, most stacks have a Design Tool that will allow you to generate this table in source code and the associated EDS file.

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