Beckhoff TwinCAT 3: EtherCAT AL Status 0x001D, Invalid Output Configuration after replacing a slave, why?
I'm getting an EtherCAT AL Status 0x001D, Invalid Output Configuration, on my TwinCAT 3 runtime. This happened after I replaced an EtherCAT slave device. The system goes into SAFEOP + error and won't reach OP. What should I check first?
The EtherCAT AL Status 0x001D indicates an invalid SyncManager configuration for output process data. This fault typically occurs during the transition from PREOP to SAFEOP at EtherCAT startup, or after a device replacement or process data modification. It prevents the slave from reaching the OPERATIONAL state.
Likely causes and checks
1Configured device revision or ESI differs from the installed device.
- Points to it
- The system detects a mismatch between the expected device configuration (vendor, product code, revision) and the actual device connected, often after a device swap or firmware update.
- Check
- Compare the configured device details (vendor, product code, revision) with the details found by an online scan in the TwinCAT System Manager.
2Output process data edited to an unsupported combination.
- Points to it
- The output process data settings have been modified to a configuration that the specific EtherCAT device does not support.
- Check
- Restore the default PDO selection from the ESI (EtherCAT Slave Information) file and only re-apply documented options for the process data.
Next check: First, perform an online scan in TwinCAT to compare the configured device's vendor, product code, and revision with the actual device found. If there's a mismatch, update the configuration to match the installed device.
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