Beckhoff TwinCAT 3 (XAR/XAE) with EtherCAT fault ADS 1793: Service not supported by the server (0x701, ADSERR_DEVICE_SRVNOTSUPP)
Beckhoff: service is not supported by the server. The ADS device on the addressed port received the request but does not implement that command or index group.
Diagnose this with AI
Try Free PLC Fault Diagnostic Upload a keypad photo, the fault history or a parameter export from your Beckhoff TwinCAT 3 (XAR/XAE) with EtherCAT. InduQT compares the evidence and suggests the next useful checks.
When it happens
- On ADS read/write/notification requests from a client or the PLC
Likely causes and checks
1Request sent to the wrong AMS port
- Points to it
- Client addresses the NC, I/O or system port with a PLC symbol service, or vice versa.
- Check
- Compare the port with the AMS port table (851 PLC, 500 NC, 300 I/O, 10000 system service).
2Index group / service not available on this TwinCAT version or device
- Points to it
- Same client works on another target; target has an older or different runtime.
- Check
- Check the index group against the device specification in ADS Basics and the target’s TwinCAT build.
Telling it apart
- ADS 1794/1795 (invalid index group/offset) mean the service exists but the address does not; 1793 means the service itself is not supported.
- ADS 6 means no server at all on the port; 1793 means a server answered and refused the service.
Evidence to collect
- Client request details (port, index group, index offset, command)
- Target TwinCAT build
- ADS Monitor / Wireshark capture of the request
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