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Siemens SINUMERIK Controller
Servo/Axis · Intermediate · 30-120 minutes
Siemens 27091 - Error in data cross check NCK-PLC, stop of
Alarm 27091 indicates that the NCK or PLC monitoring channel has triggered a Stop D or Stop E function, halting program execution. This is a secondary alarm that always references alarm 27090, which contains the actual root cause of the safety-related stop.
27091
Siemens 27091 - Error in data cross check NCK-PLC, stop of
Error in data cross check NCK-PLC, stop of
The monitoring channel specified in (NCK or PLC) has triggered a stop D or E (depending on the parameterization in MD $MN_SAFE_SPL_STOP_MODE). The alarm 27090 provides further information about the cause for the stop D/E Control reaction: Alarm display. Trigger a STOP D/E (settable via MD $MN_SPL_STOP_MODE) on all axes with safety functionality, as soon as the SPL setup phase (MD $MN_PREVENT_SYNACT_LOCK[0,1] unequal to 0) is completed.
Root Cause Summary
Alarm 27091 indicates that the NCK or PLC monitoring channel has triggered a Stop D or Stop E function, halting program execution. This is a secondary alarm that always references alarm 27090, which contains the actual root cause of the safety-related stop.
Safety
- Drive/power/encoder circuit: hazardous voltages may remain in the DC link after power-off. Lock out / tag out, wait for discharge per the drive documentation, and use qualified personnel only.
Causes and Fixes
- 1
Check alarm 27090 in the alarm buffer (Diagnostics > Alarm History) to identify the specific safety condition that triggered the stop. Note the monitoring channel identifier in parameter %1.
Do not restart the program until the root cause from 27090 is resolved.
- 2
Navigate to Siemens SINUMERIK 840D HMI: Diagnosis > Parameters > Machine Data (MD). Review MD $MN_SAFE_SPL_STOP_MODE to confirm Stop D (1) or Stop E (2) configuration matches your safety requirements.
- 3
Verify axis limit parameters (MD $MN_AXCONF_LIMIT_MIN_1 / _MAX_1, etc.) and encoder deviation tolerance (MD $MN_SAFE_LIMIT_DIFF) are within acceptable range for current workpiece geometry and feed rates.
- 4
Clear alarm 27091 by pressing RESET key on control panel. Part program must be restarted from beginning; no resumption is permitted after safety stop.
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