231-9220

Access machine parameters

Press MOD key, select 'Machine Parameters' from the TNC menu, navigate to the servo axis configuration section.

Always backup current parameters before making changes using the parameter export function.

Locate speedEncoderInput parameter

Find the speedEncoderInput parameter for the affected axis in the servo configuration group (typically MP7xx series parameters).

Document original values before modification - incorrect changes can damage servo drives.

Verify parameter value range

Check that the speedEncoderInput value matches available encoder input channels (typically 0-3 for standard TNC configurations).

Consult the machine manufacturer's parameter list for valid input channel assignments.

Apply and test configuration

Save parameters, perform PLC restart (Ctrl+Alt+Del in TNC), and verify alarm clearance during system initialization.

Check PWM output assignment

In machine parameters, locate the PWM output configuration (typically MP6xx series) and note which output channel is assigned to the affected axis.

Use the TNC diagnostic screen (DIAG key) to monitor real-time PWM output signals.

Verify encoder input wiring

Physically trace the speed encoder feedback cable from the servo drive to the TNC encoder input connector, confirming it matches the configured input channel.

Cross-reference parameter consistency

Ensure the speedEncoderInput parameter value corresponds to the physical encoder input channel receiving feedback from the servo drive connected to the configured PWM output.

Mismatched assignments can cause runaway conditions - verify all connections before enabling servo power.

Update parameter alignment

Modify either the speedEncoderInput parameter or PWM output assignment to create proper correspondence, then restart the control system.

Perform encoder input diagnostics

Access TNC diagnostics (DIAG key), navigate to 'Encoder Inputs' section, and check status of the configured speed encoder input channel.

Look for 'Signal Present' indicators and frequency readings to verify encoder functionality.

Inspect physical connections

Check encoder cable connections at both TNC input connector and servo drive output, looking for loose pins, damaged cables, or corrosion.

Power down the system before disconnecting encoder cables to prevent damage to input circuits.

Test with known good encoder

Temporarily connect a verified working encoder to the suspected input channel to isolate whether the issue is hardware or configuration related.

Use an oscilloscope to verify proper encoder signal levels (typically 5V TTL or differential RS-422).

Replace faulty hardware components

If hardware failure is confirmed, replace the encoder input board or servo drive encoder output section as required.

Check TNC software version compatibility

Press HELP key, select 'Version Info' to verify current TNC software version matches the machine parameter set requirements.

Keep a log of software versions and corresponding parameter backups for quick restoration.

Restore factory default parameters

Load machine manufacturer's original parameter set from backup or factory defaults, focusing on servo configuration sections.

Factory reset will erase all custom settings - document current tool tables and work offsets first.

Reconfigure speedEncoderInput systematically

Manually reconfigure the speedEncoderInput parameter using known good values, testing each axis individually before proceeding to the next.

Configure one axis at a time and test servo enable to isolate any remaining issues.