Troubleshooting¶
Symptoms, causes and fixes, cheapest check first.
| Symptom | Cause | Fix |
|---|---|---|
sdoDownloadExpedited() returns false, nothing on the bus |
size is not 1, 2 or 4 |
Use the size of the object's type |
| Every call returns false | Your send() fails: controller not started, bus-off, TX queue full |
Check the controller is initialised, termination (60 Ω between CAN_H and CAN_L with power off), bit rate |
| Frames on the bus, error frames follow | No other node acknowledges, or bit rates differ | Power the node; set the same bit rate everywhere (500 kbit/s on Vortex V1) |
| Node ignores NMT | Wrong node ID, or the node has not finished booting | Wait for its boot-up message (0x700 + node, one byte 0x00); check the ID |
SDO abort from the node (0x580 + node, byte 0 0x80) |
Object missing, read-only, wrong size or value out of range | Bytes 4 to 7 hold the CiA 301 abort code; check the EDS |
| CiA 402 drive does not reach Operation enabled | A command was sent before the previous state was reached, or the drive is in Fault | Read the statusword (0x6041) between steps; send Fault reset (0x0080) first |
| Motor does not move although enabled | Mode of operation not set, or no target written | Write 0x6060 and the target object for that mode |
Next: API reference.