BUSMASTER CANopen: Transfer files with SDO

Applies to BUSMASTER 3.2.2.50.

11. Segmented and Block file transfers

The ordinary SDO editor accepts up to 4 KiB; file SDO accepts up to 16 MiB. A device object may have a smaller limit. Keep the file exercise plan set to Once.

Transfer mode	When to use it
Automatic SDO	Uses the appropriate expedited or segmented transfer; it does not automatically select Block
Segmented SDO	Explicit segmented transfer; use this for the teaching DOMAIN read/write exercises
Block SDO	Use with a peer that supports Block; inspect negotiation, progress and the final result. The teaching peer does not demonstrate this mode.

Empty input files can use automatic or segmented transfer when the target object allows empty data. Block does not accept an empty input file. SDO response timeout controls response waiting, rather than the total duration allowed for a large file.

Read from the node and save a file

1. Select SDO, Read / upload, Segmented SDO, node 8, index 0x2100, sub-index 0 and Once.
2. Select Tools… → Read node data and save file… (读取节点数据并保存文件…). Choose a new filename, such as domain-read.bin.
3. Inspect the preview, start sending and wait for transfer and save completion at the bottom.
4. The teaching initial data has 6145 bytes. Compare it byte for byte or by SHA-256 with the initial-data download in chapter 1. If the node data has changed, compare against the known file you just wrote instead.

Write from a file and read it back

1. First read and save the original data as above. Check that teaching object 0x2100:0 is writable.
2. Check the node, address, segmented mode and Once plan. Select Tools… → Write file to node… (将文件写入节点…) and choose the practice file.
3. Inspect the object and byte count, start sending and wait for the whole transaction.
4. Read back into another new file. Compare input and readback lengths and SHA-256 values.
5. Write the saved original data back and read it again afterward.

Output files are saved without directly overwriting an existing file. Choose a new name and wait for the transfer and save results. To cancel, stop the task in Send tasks…. After stopping a write, perform SDO recovery if requested, then read the target object to inspect its current contents.

Block size (1–127) and CRC are configured under Settings… → Advanced parameters. Start with the defaults, then adjust according to the Block-capable device requirements.

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