230-007E

Access Reference Point Menu

Press MOD key, select 'Reference Point' or navigate to Setup > Machine > Reference Point menu on the TNC control.

On newer TNC controls, use the machine operating panel's REF button for direct access.

Execute Reference Run

Select the affected axis and press NC START to initiate the reference run. Monitor axis movement to reference switch and encoder reference mark.

Ensure axis travel path is clear and all safety devices are functional before starting reference run.

Verify Reference Status

Check that the axis shows 'REF' status in the position display and verify MP1200 (reference point validity) shows '1' for the affected axis.

Use PLC > Inputs/Outputs menu to monitor reference switch states during troubleshooting.

Check Encoder Connections

Verify encoder cable connections at both encoder and TNC drive interface. Check for loose connections, damaged cables, or contamination on connector pins.

Use the TNC's encoder test function in the service menu to verify signal quality and reference mark detection.

Monitor Reference Mark Signal

Access TNC Setup > Machine > Encoder menu and observe the reference mark signal (R signal) during manual axis movement past the reference position.

Only qualified personnel should access encoder diagnostic functions as incorrect settings can damage the drive system.

Verify MP3200 Settings

Check machine parameter MP3200 (encoder type) and related encoder configuration parameters match the installed encoder specifications.

Compare encoder nameplate data with TNC parameter settings, particularly resolution and reference mark specifications.

Test Reference Switch Operation

Navigate to PLC > Inputs/Outputs and manually actuate the reference switch while monitoring its input status on the TNC display.

Reference switches typically use inputs starting from X121 onwards - check your machine documentation for specific assignments.

Check Switch Positioning

Verify reference switch is properly positioned and actuated by the axis cam or dog. Adjust switch position if necessary to ensure reliable activation.

Maintain proper switch actuation distance - too close may cause false triggering, too far may prevent detection.

Verify PLC Logic

Check PLC program logic for reference switch processing and ensure MP1010 (reference switch input assignment) correctly maps to the physical input.

Use TNC's PLC status display to trace signal flow from input through to reference detection logic.

Review Active Kinematic

Access Setup > Machine > Kinematics and verify the active kinematic configuration matches the actual machine setup and all axes are properly defined.

Check that all axes in the kinematic have valid channel assignments and are not duplicated across channels.

Verify Axis Configuration

Check MP1000 series parameters for axis assignment and ensure each axis in the kinematic has proper reference method defined in MP1020.

Incorrect kinematic configuration can cause unexpected machine behavior - document current settings before making changes.

Test Individual Axis Reference

Temporarily remove the problematic axis from the kinematic and test its reference capability independently to isolate configuration issues.

Use the axis test functions in the service menu to verify individual axis reference capability outside of kinematic constraints.

Check Drive Status LEDs

Examine the status LEDs on the servo drive module for the affected axis. Look for error indicators or communication fault displays.

Heidenhain drives typically show green for ready, red for fault - consult drive manual for specific LED patterns.

Verify Communication Parameters

Check MP2000 series parameters for drive communication settings including baud rate, node address, and protocol configuration.

Incorrect communication parameters can cause multiple axis failures - verify settings against drive documentation.

Test Drive Communication

Use TNC diagnostic functions to test communication link with the drive and verify proper data exchange for position and status information.

The TNC's drive diagnostic menu can show real-time communication status and error counters for troubleshooting.