What causes FANUC alarm 357?

An axis specified in the composite control G-code block is already assigned to a synchronous control pair, creating a conflict.. The part program attempts to activate composite control on an axis that is currently under superimposed control without canceling it first.. Duplicate axis assignment in the composite control command where the same axis appears in more than one active control mode simultaneously.. A previous composite or synchronous control block was not properly canceled with the appropriate G-code before a new composite control command was issued.. Parameter settings for axis grouping conflict with the axis assignments called out in the CNC program..

How do I fix FANUC alarm 357?

1. Review the part program around the line that triggered the alarm and identify which axis is being called into composite control. Check if that same axis is already active in a synchronous, superimposed, or another composite control block earlier in the program. 2. Search the program for all composite control G-codes (typically G125 or machine-specific codes) and verify that each activation has a matching cancel command before a new composite control block is started on the same axis. 3. Check for any superimposed control G-codes (such as G126) that may still be active on the target axis. Cancel superimposed control before attempting composite control on that axis. 4. Verify the axis grouping parameters (typically PMC or machine parameters related to multi-path control) to ensure no axis is permanently assigned to a conflicting control mode at the parameter level. 5. If the machine has multiple paths, confirm that the axis in question is not being commanded from two paths simultaneously. Coordinate the program flow between paths so control modes are properly handed off. 6. After making corrections, reset the alarm, perform a program dry run in single block mode, and step through the composite control activation sequence to confirm no conflicts occur.

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FANUC Controller

Servo/Axis · Intermediate · 30-60 minutes

Alarm 357

Fanuc Alarm 357 - COMPOSITE CONTROL AXIS COMPOSITION ERROR

Alarm 357 occurs when the CNC attempts to engage composite control on an axis that is already participating in another synchronization mode (tandem, superimposed, or composite control). This is a parameter configuration conflict or improper M-code/G-code command sequence that violates the mutual exclusivity of these control modes.

FANUCServo/AxisIntermediate30-60 minutes

357

Fanuc Alarm 357 - COMPOSITE CONTROL AXIS COMPOSITION ERROR

FANUC ALARM 357

Root Cause Summary

Alarm 357 occurs when the CNC attempts to engage composite control on an axis that is already participating in another synchronization mode (tandem, superimposed, or composite control). This is a parameter configuration conflict or improper M-code/G-code command sequence that violates the mutual exclusivity of these control modes.

Causes and Fixes

1
Navigate to SYSTEM > PARAM and check parameter 1022 (slave axis number) and 1023 (slave axis direction). If these are set for the alarmed axis, synchronous control is already active.
2
Check parameters 8150 (composite control enable), 8151-8159 (composite axis assignments). Verify no duplicate axis assignments exist across composite groups.
3
Review the part program or macro executing when alarm occurred. Look for G51.2/G51.3 (composite control commands) being issued without proper G50.2/G50.3 cancellation of prior synchronization.
4
Issue a reset and manually execute cancellation commands (G50.2, G50.3, or M-code that cancels synchronous control per ladder) before attempting composite control activation.
Ensure machine is in a safe position before canceling synchronization modes as axes may move independently

DIY Feasiblehigh confidence

Call a technician if:

·Parameter corruption suspected
·Hardware I/O issues with control signals
·Persistent alarm after all software solutions attempted

Prevention

Always include explicit control mode cancellation commands before activating new control modes
Use program structure with proper sequencing and dwell times between control mode changes
Regularly backup and verify parameters 1820-1889 for control mode settings
Implement program templates with standardized control mode activation/deactivation sequences

Common Mistakes

Attempting to activate composite control without first canceling active synchronous control
Not allowing sufficient time for control mode transitions to complete
Overlooking active MPG or superimposition modes before composite control activation
Using RESET button without properly understanding which control modes remain active after reset

Related Alarms

356 358 359 1430 1431

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