230-045D

Check Reference Status

Navigate to MOD > Machine > Axis Status and verify the reference status flags for the affected axis. Look for REF indicator showing multiple reference states.

Use the axis status display to see if REF flag is blinking, indicating an incomplete reference cycle

Clear Reference Memory

Go to MOD > Machine > Clear Reference and select the affected axis to clear existing reference data before attempting new reference run.

Clearing reference will require complete re-homing of the machine

Execute Single Reference Cycle

Perform manual reference run using Manual > Reference Run menu, ensuring only one reference cycle is executed per axis.

Monitor the reference offset value in real-time during the reference run to ensure it's set only once

Verify MP7500 Settings

Access MOD > Machine Parameters and check MP7500.x for the affected axis. Ensure reference method is correctly set (0=no ref, 1=ref switch, 2=absolute encoder).

MP7500 should match your actual hardware configuration - mixing absolute and incremental settings causes reference conflicts

Check MP7510 Reference Offset

Verify MP7510.x (Reference point offset) is not being overwritten by multiple sources. Check if PLC or NC program is modifying this parameter.

Never modify MP7510 while machine is in automatic mode

Validate MP7520 Reference Direction

Confirm MP7520.x (Reference direction) matches physical switch/encoder setup. Incorrect direction can cause multiple reference attempts.

Use machine diagnostic screen to observe reference switch states during manual axis movement

Monitor PLC Reference Markers

Open PLC > Marker Status and observe M7500.x (Reference enable) and M7510.x (Reference active) for the affected axis during reference operations.

M7500 should pulse once per reference cycle - continuous high signal indicates PLC logic error

Check PLC Reference Program

Review PLC program sections handling reference logic, particularly any loops or conditions that might retrigger reference commands.

Backup PLC program before making any modifications

Verify Reference Interlock Logic

Examine PLC interlocks that control reference sequence timing to ensure proper sequencing and no overlapping reference commands.

Use PLC trace function to monitor reference signal timing and identify multiple trigger events

Test Reference Switch Operation

Navigate to MOD > Diagnosis > Digital Inputs and manually trigger reference switches while observing input status changes.

Reference switch should show clean on/off transitions - bouncing or intermittent signals indicate hardware problems

Check Encoder Communication

Access MOD > Diagnosis > Encoder and verify communication status, error counters, and position validity for absolute encoders.

Encoder communication errors can cause position loss requiring complete re-referencing

Verify Cable Connections

Inspect encoder and reference switch cable connections at both machine and control ends for loose connections or damage.

Use oscilloscope to check encoder signal quality if communication errors persist

Search Program for Reference Commands

Use Program > Search function to locate all instances of G74, G75, or other reference-related commands in active NC programs.

Check both main program and all called subroutines for reference commands

Review Program Logic

Examine program flow to ensure reference commands are not executed multiple times through loops or repeated subroutine calls.

G74 should only be used once per axis per program cycle

Test Program in Single Block

Run problematic program in single block mode to identify exactly which command triggers the duplicate reference alarm.

Use program trace to monitor reference-related modal states during program execution