280-0930

Check C-axis reference status

Press POS key and verify if C-axis shows REF status. If not referenced, the axis will show dashed lines or question marks.

On newer TNC controls, unreferenced axes are clearly marked with a different color in the position display.

Execute C-axis referencing

Go to Manual Operation mode, select the C-axis (spindle), and press REF+ or REF- to initiate reference point approach.

Ensure no tools or workpieces will interfere with spindle rotation during referencing.

Verify reference completion

Confirm C-axis shows REF status and displays actual angular position values instead of dashes.

The reference process should complete within one full spindle revolution.

Check encoder diagnostics

Access MOD function, go to System Info, then Axis Diagnostics to check C-axis encoder status and error counters.

Look for encoder error flags or unusual position deviation values.

Inspect encoder connections

Verify encoder cable connections at both the encoder and the TNC control cabinet. Check for loose connections, damaged cables, or contamination.

Power down the system before checking electrical connections.

Test encoder functionality

Manually rotate the spindle slightly and observe if position values change smoothly in the position display.

Erratic position readings or no change in values indicates encoder problems.

Access machine parameters

Press MOD key, enter machine parameters menu, and navigate to MP7500 series parameters for spindle configuration.

Machine parameter changes require appropriate access level and should be documented.

Verify spindle type setting

Check MP7500.x bit settings to ensure the spindle is configured as a positioning spindle with C-axis capability.

Bit 0 typically enables C-axis functionality - it should be set to 1.

Restart control after changes

If parameters were modified, perform a control restart to activate the new spindle configuration settings.

Always backup machine parameters before making changes.

Check cycle parameters

Review the active measurement cycle (CYCLE 31, 32, or custom probing cycle) parameters to verify spindle angle requirements are properly specified.

Look for parameters related to spindle orientation or angular positioning in the cycle definition.

Verify tool table entries

Access tool table and check if the tool being measured has proper entries for number of teeth and angular orientation if required.

Some measurement cycles require the number of cutting edges to be defined in the tool table.

Modify cycle call

If using a probing cycle, ensure the spindle angle parameter is either specified or set to allow automatic positioning.

Setting spindle angle to 0 or omitting the parameter may resolve the alarm if exact positioning is not critical.