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FANUC Controller
Program/G-code · Intermediate · 5-30 minutes
Fanuc 258 - Tool not found in group
Alarm 258 occurs when the control cannot locate a specified tool within a defined tool group during program execution. This typically happens when a T-code or tool offset number is called that doesn't exist in the group table, or when tool group management is enabled but not properly configured. The alarm is a safeguard to prevent the machine from attempting operations with undefined or improperly assigned tools.
258
Fanuc 258 - Tool not found in group
TOOL NOT FOUND IN GROUP
Fanuc PS program alarm 258: TOOL NOT FOUND IN GROUP. This alarm is triggered by an illegal or incorrectly formatted command in the part program, or a programming condition that the Fanuc control cannot execute.
Root Cause Summary
Alarm 258 occurs when the control cannot locate a specified tool within a defined tool group during program execution. This typically happens when a T-code or tool offset number is called that doesn't exist in the group table, or when tool group management is enabled but not properly configured. The alarm is a safeguard to prevent the machine from attempting operations with undefined or improperly assigned tools.
Safety
- Verify corrected program or parameters before resuming machining
Causes and Fixes
- 1
Identify the T-code or tool number from the program line where the alarm occurred and write it down.
- 2
Access the tool management or tool group table (typically OFFSET SETTING screen, then tool group management pages or parameter-based group tables).
- 3
Verify the called tool number exists in the currently active tool group. Check both the group assignment and tool registration.
- 4
Either add the missing tool to the group table or correct the T-code in the part program to match an existing tool in the group, then reset and restart.
Ensure tool pocket assignments and offsets are correctly entered when adding tools to groups to prevent crashes.
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