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Siemens SINUMERIK Controller
Servo/Axis · Basic · 10-20 minutes
Siemens 840D 16926 - Channel channel coordination: action not allowed in block,
The action was denied, the marker was already set. Check the program. Example: SETM(1); CLEARM(1); Marker must be reset first. SETM(1)
16926
Siemens 840D 16926 - Channel channel coordination: action not allowed in block,
Channel channel coordination: action not allowed in block,
The action was denied, the marker was already set. Check the program. Example: SETM(1); CLEARM(1); Marker must be reset first. SETM(1)
Safety
- Refer to Siemens documentation
- Ensure qualified technician performs repairs
Common Causes
- Marker already set when attempting to execute action without proper reset sequence
- Program logic error where SETM and CLEARM commands are executed in incorrect sequence
- Missing or improperly placed marker reset (CLEARM) instruction before subsequent SETM commands
- Conflicting channel coordination commands in rapid succession without synchronization
Troubleshooting Steps
- 1Review the NC program block sequence around the error location to identify the marker state at time of alarm
- 2Verify CLEARM command is executed before attempting another SETM command for the same marker
- 3Check channel coordination logic to ensure markers are properly managed between channel switching operations
- 4Trace marker usage throughout the complete program to identify duplicate SETM calls without intervening CLEARM
- 5Reload program after correcting sequence and execute dry run to confirm marker state transitions
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