What causes FANUC alarm 200?

Part program contains an illegal or malformed command related to the alarm condition. Missing required address word or parameter value in the program block. Programmed value is out of the allowable range. Conflict between active modal codes and the commanded function. Post-processor configuration mismatch for this Fanuc series.

How do I fix FANUC alarm 200?

1. Note the block number shown in the alarm screen and locate that block in the program. 2. Review the command in that block against the Fanuc programming manual. 3. Check for missing words, incorrect values, or conflicting G-code combinations. 4. Verify the program is post-processed for the correct Fanuc series. 5. Correct the program and dry-run at low speed before resuming machining.

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FANUC Controller

Program/G-code · Intermediate · 15-30 minutes

Alarm 200

Fanuc Alarm 200 - Data Read Error

Alarm 200 occurs during rigid tapping (G84/G74) when the spindle speed S command is missing, zero, or outside the allowable range defined by spindle parameters. This alarm specifically validates that the S code falls within the minimum and maximum spindle speed limits and is properly formatted for the rigid tap cycle.

FANUCProgram/G-codeIntermediate15-30 minutes

200

Fanuc Alarm 200 - Data Read Error

Read Failure

Root Cause Summary

Alarm 200 occurs during rigid tapping (G84/G74) when the spindle speed S command is missing, zero, or outside the allowable range defined by spindle parameters. This alarm specifically validates that the S code falls within the minimum and maximum spindle speed limits and is properly formatted for the rigid tap cycle.

Safety

Data not loaded

Causes and Fixes

1
Review the NC program at the alarm line. Verify that the G84 (right-hand tap) or G74 (left-hand tap) block contains an explicit S command with a non-zero value (e.g., G84 Z-30. R2. F100 S500).
2
Check if a previous block contained S0 which cancels the spindle speed. Insert a valid S code before or within the rigid tapping block.
3
Navigate to SYSTEM > CURRENT (POSITION page) and verify the current modal S value shows a valid spindle speed, not zero or blank.
4
If using canned cycle modal programming, ensure the initial G84/G74 block includes the S code, as subsequent blocks may inherit other values but not always the S code depending on parameter 5101 settings.

DIY Feasiblehigh confidence

Call a technician if:

·Encoder hardware failure suspected
·Parameter changes don't resolve issue
·Spindle motor problems indicated

Prevention

Always specify appropriate S values in rigid tapping cycles
Regularly verify spindle encoder operation
Document parameter changes for future reference

Common Mistakes

Using S0 in rigid tapping blocks
Forgetting to enable rigid tapping in parameter 5200
Setting S values above parameter limits without checking

Related Alarms

201 202 410 411

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