230-041F

Access machine parameters

Press MOD key, select 'Machine Parameters', navigate to CfgAxisHardware configuration object for the affected axis.

Use the search function in machine parameters by typing 'posEncoderIncr' to quickly locate the parameter.

Verify posEncoderIncr value

Check that posEncoderIncr matches your encoder specification. For rotary encoders, typical values are 1024, 2048, 4096, or 5000 increments per revolution.

Never set posEncoderIncr to zero or negative values as this will trigger the alarm.

Calculate correct increment value

For motor encoders: use encoder lines × 4 (quadrature). For linear encoders: use 1/signal period in µm (e.g., 20µm signal period = 0.05 increments per µm).

Consult encoder manufacturer datasheet for exact specifications before making changes.

Apply and restart

Save parameter changes, perform PLC restart via MOD → Reset → PLC Reset to validate new configuration.

Backup machine parameters before making changes using the data backup function.

Locate posEncoderDist parameter

In MOD → Machine Parameters → CfgAxisHardware, find posEncoderDist for the affected axis shown in the alarm message.

The axis number in the alarm (%2) corresponds to the internal axis numbering, not necessarily the axis name.

Verify mechanical specifications

For rotary axes: enter 360.000 degrees. For linear axes: enter the distance traveled per encoder revolution (ball screw pitch in mm).

Incorrect posEncoderDist values will cause severe positioning errors even if the alarm is cleared.

Cross-check with drive system

Verify ball screw pitch from machine documentation. Common values are 5mm, 10mm, 16mm, 20mm, or 25mm per revolution.

For belt drives, calculate effective pitch as: belt pitch × drive pulley teeth ÷ driven pulley teeth.

Validate parameter relationship

Ensure posEncoderIncr and posEncoderDist create realistic resolution. Calculate: posEncoderDist ÷ posEncoderIncr should give reasonable µm per count.

Typical resolutions range from 0.1µm to 10µm per encoder count for machine tools.

Check parameter history

Review recent parameter changes in MOD → Machine Parameters → Parameter Log to identify when corruption occurred.

Look for batch parameter changes or restore operations that coincide with alarm onset.

Compare with known good backup

Load a verified backup from before the alarm started, or compare current values with machine documentation/commissioning records.

Only restore parameters if you have a verified good backup from the same software version.

Restore encoder parameters

Manually enter correct posEncoderIncr and posEncoderDist values based on machine specifications or previous working configuration.

Document all parameter changes in the machine logbook for future reference.

Perform full validation

After parameter correction, run encoder test functions and verify axis movement accuracy with test programs.

Always verify axis movement direction and scaling after encoder parameter changes.

Verify encoder hardware specifications

Check encoder nameplate or documentation for actual increment count and confirm it matches the installed hardware.

Use encoder manufacturer's part number to look up exact specifications online.

Update parameters for new encoder

Modify posEncoderIncr to match new encoder resolution and verify posEncoderDist remains correct for mechanical system.

Encoder changes may also require updates to other parameters like maximum encoder frequency limits.

Recalibrate reference points

After parameter update, establish new reference points using MOD → Manual Operation → Set Reference Point for affected axes.

Mark physical reference positions on machine before starting calibration process.