239-01B1

Check EnDat cycle time parameters

Navigate to MOD function → Machine Parameters → Axis-specific parameters → MP7440 (EnDat cycle time). Check if values are below 125μs for high-resolution encoders.

Start with 250μs and increase gradually until alarm clears

Verify encoder resolution settings

Check MP4110 (Linear/rotary encoder input) and MP4130 (Reference marks) to ensure encoder resolution matches actual hardware specifications.

Incorrect resolution settings can cause data overflow

Adjust communication timing

Increase MP7440 values incrementally by 50μs steps until communication stabilizes. Monitor PLC program execution time in diagnostic screens.

Use TNCopt to optimize cycle times after resolving the alarm

Identify encoder configuration

Check MOD → Machine Parameters → MP4110 for all axes to identify EnDat encoders and their resolution settings. Count total active high-resolution encoders.

Encoders above 5 million counts/rev are most likely to cause issues

Stagger encoder communication cycles

Modify MP7440 values for different axes to create staggered communication timing. Set axis 1 to 250μs, axis 2 to 275μs, etc.

Do not set cycle times below manufacturer minimum specifications

Consider encoder resolution reduction

If precision allows, reduce encoder resolution in MP4110 or switch to 1Vpp mode for non-critical axes to reduce telegram frequency.

Rotary axes often don't need maximum resolution and can be optimized first

Check encoder diagnostic data

Navigate to MOD → Diagnosis → Encoder diagnosis. Look for error counters, temperature warnings, or communication errors on individual encoders.

EnDat encoders report internal diagnostics - use this data to identify failing units

Isolate problematic encoder

Temporarily disconnect encoders one by one (with machine power off) and restart to identify which encoder triggers the alarm.

Always power down completely before disconnecting encoder cables

Verify cable integrity

Check encoder cable continuity and shielding. Measure cable resistance and check for intermittent connections that could cause communication retries.

Use an oscilloscope to check EnDat signal quality if available

Check PLC cycle time

Monitor PLC program execution time in MOD → Diagnosis → PLC status. Look for cycle times exceeding 10ms or irregular timing patterns.

Optimize PLC program by reducing unnecessary calculations in fast loops

Review I/O configuration

Check MP7500 series parameters for I/O module configuration. Verify that I/O update rates are not set too aggressively for the system capacity.

Excessive I/O polling can saturate the communication bus

Monitor system temperature

Check CC module temperature in diagnostic screens. Overheating can reduce processing capacity and cause communication delays.

Clean cabinet filters and verify cooling fan operation if temperatures are elevated

Review EnDat monitoring parameters

Check MP7441 settings in MOD → Machine Parameters. Verify monitoring level is appropriate for application requirements.

Reduce monitoring level temporarily to test if this resolves the alarm

Disable unnecessary diagnostic features

Turn off continuous temperature monitoring or advanced diagnostic features in MP7441 if not required for the application.

Document original settings before making changes

Optimize monitoring schedule

Configure MP7441 to perform diagnostic checks at longer intervals rather than continuous monitoring to reduce telegram frequency.

Schedule intensive diagnostics during machine idle periods if possible