What causes FANUC alarm 355?

Composite control axis parameter references an axis number that does not exist. Conflicting axis assignments between composite control and other axis groupings. Same axis assigned to both composite control and another synchronized function. Parameter value out of the valid range for composite control axis index. Parameter restored from different machine with different axis configuration.

How do I fix FANUC alarm 355?

1. Check the composite control axis parameters for valid axis numbers. 2. Verify no axis conflicts between composite control and synchronous or superimposed control assignments. 3. Power cycle after parameter correction. 4. Consult the machine builder parameter list for correct composite control configuration.

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FANUC Controller

Program/G-code · Intermediate · 30-60 minutes

Alarm 355

Fanuc Alarm 355 - PARAMETER OF INDEX OF COMPOSITE CONTROL AXIS SET ERROR

Alarm 355 COMPOSITE CONTROL AXIS SET ERROR occurs when parameter No. 8183 contains an invalid axis number or configuration for composite control (tandem/synchronous control). This typically happens during initial setup, after axis reconfiguration, or when parameter data becomes corrupted. The composite control axis specified does not match available physical axes or violates composite control pairing rules.

FANUCProgram/G-codeIntermediate30-60 minutes

355

Fanuc Alarm 355 - PARAMETER OF INDEX OF COMPOSITE CONTROL AXIS SET ERROR

PARAMETER OF INDEX OF COMPOSITE CONTROL AXIS SET ERROR

Root Cause Summary

Alarm 355 COMPOSITE CONTROL AXIS SET ERROR occurs when parameter No. 8183 contains an invalid axis number or configuration for composite control (tandem/synchronous control). This typically happens during initial setup, after axis reconfiguration, or when parameter data becomes corrupted. The composite control axis specified does not match available physical axes or violates composite control pairing rules.

Causes and Fixes

1
Navigate to SYSTEM > PARAM and verify parameter 0020 (number of controlled axes). Note the total axes configured.
2
Check parameter 8183 (composite control axis number). Verify the value does not exceed the number in parameter 0020 and is a valid axis number (1-8 for most systems, 1-24 for 30i/31i/32i).
Parameter write enable (PWE) must be set to 1 before modifying parameters. Record original values before changes.
3
If parameter 8183 contains an invalid axis number, correct it to match the intended composite axis (typically the slave axis in tandem control). Set to 0 if composite control is not used.
4
Power cycle the CNC control after parameter modification and verify alarm clears. Check DIAGNOSIS > SERVO > axis status to confirm composite control is functioning.

DIY Feasiblehigh confidence

Call a technician if:

·Parameter corruption suspected
·Hardware changes involved
·Composite control option not licensed

Prevention

Always backup parameters before making composite control changes
Verify axis configuration before setting composite parameters
Document all tandem/gantry axis assignments

Common Mistakes

Setting parameter 8183 before enabling composite control in 8180
Referencing non-existent axis numbers
Not updating composite parameters after hardware changes

Related Alarms

354 356 400 401

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