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FANUC Controller
Program/G-code · Basic · 10-20 minutes
Fanuc Alarm 056 - NO END POINT & ANGLE IN CHF/CNR
Alarm 056 indicates the chuck clamping confirmation signal is not detected when the machine attempts to execute a cycle start or spindle rotation command. This is typically caused by the chuck pneumatic/hydraulic pressure not being sufficient, a faulty chuck clamp proximity sensor (limit switch), or incorrect PMC ladder logic configuration for the interlock chain.
056
Fanuc Alarm 056 - NO END POINT & ANGLE IN CHF/CNR
NO END POINT & ANGLE IN CHF/CNR
Fanuc PS056: A chamfering or corner rounding command requires both an end point and an angle, but one or both are missing from the block. Both values must be specified for this type of CHF/CNR command.
Root Cause Summary
Alarm 056 indicates the chuck clamping confirmation signal is not detected when the machine attempts to execute a cycle start or spindle rotation command. This is typically caused by the chuck pneumatic/hydraulic pressure not being sufficient, a faulty chuck clamp proximity sensor (limit switch), or incorrect PMC ladder logic configuration for the interlock chain.
Safety
- Workpiece not secured
Causes and Fixes
- 1
Verify hydraulic/pneumatic pressure gauge reads within specification (typically 40-60 bar hydraulic, 5-7 bar pneumatic). Check for leaks in chuck actuator lines, rotary union, and cylinder seals.
Lock out spindle rotation and use chuck wrench to manually verify jaw position before pressure checks
- 2
Navigate to FANUC PMC screen: SYSTEM > PMC > PMCDGN > press soft key [SIGNAL] > [G] to monitor G address signals. Manually activate chuck clamp solenoid and confirm G124.x (chuck clamp confirm bit) changes from 0 to 1.
- 3
Inspect chuck clamp proximity sensor mounting position. Sensor should be 0.5-2mm from target surface when jaws are fully clamped. Clean metal chips and coolant residue from sensor face.
- 4
Test proximity sensor by measuring DC voltage at sensor terminals (typically 24VDC supply). Sensor output should switch from 0V to +24V (NPN) or +24V to 0V (PNP) when metal target is presented within sensing distance.
Call a technician if:
- ·PMC ladder modification required
- ·Hydraulic system rebuild needed
- ·Chuck mechanism replacement required
Prevention
- Perform weekly chuck pressure checks
- Monitor hydraulic fluid condition monthly
- Clean chuck position sensors during PM
- Backup parameters after any chuck modifications
Common Mistakes
- Ignoring hydraulic pressure warnings
- Adjusting sensors without proper chuck positioning
- Modifying PMC ladder without understanding interlock logic
- Operating with contaminated hydraulic fluid
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