Siemens alarm 25110: Axis %1 selected encoder not available
SINUMERIK axis/spindle alarm · Siemens 840D/810D powerline
What it means
A program, PLC job or function addressed an encoder number of the axis that is not configured, so the selection was rejected. Typically the second encoder was never commissioned although downstream logic assumes it exists.
Likely causes
- encoder 2 set to simulated (MD 30240[2] = 0) while being selected
- encoder index out of the configured range
- machine data lost/reset after service, removing the second encoder configuration
Need the part urgently?
Send us alarm 25110 with your machine details — typical RFQ turnaround is 24–48h.