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Common Issues with EDDY Sensor

Error Error during homing z: Eddy current sensor error During Homing​

When encountering this error, troubleshoot in the following order.

Update Klipper or System​

Important Notice

The Z-homing functionality of EDDY previously had compatibility issues, which have been optimized in the Klipper update from January 6, 2026.

  • Standard上位机: Update Klipper to a newer stable version.
  • FLY上位机: Upgrade the system version to V1.3.5 or higher.

After completing the update, re-calibrate the EDDY.

Adjust Drive Current​

  1. Open the printer.cfg file.
  2. Find the reg_drive_current = parameter at the bottom of the configuration.
  3. Increase or decrease the current value by 1, for example, change 15 to 16 or 14.
  4. Enter the calculated result directly; do not use expressions like 15+1.
  5. Save the file and restart the printer, then retest homing.
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Adjust Probe Offset​

If the issue persists after updating and adjusting the drive current, check z_offset.

  1. Locate the [probe_eddy_current fly_eddy_probe] configuration section in printer.cfg.
  2. Increase the z_offset: value appropriately. The default is usually 1.0. Try 2.0 or 2.5 first.
  3. This parameter should only be set once in this configuration section; do not duplicate it.
  4. It is recommended not to exceed 3.0. The final value depends on your machine's structure and probe mounting height.
  5. Save and restart the printer, then test homing again.
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Warning !! probe_eddy_current sensor not in valid range​

This error indicates the probe reading is outside the valid range. A common cause is that after enabling the EDDY probe, the probing height specified in other configuration sections does not take effect as expected, causing the probe to move beyond its physical range.

Please check the following locations:

  • [probe_eddy_current fly_eddy_probe]
  • [bed_mesh]
  • [z_tilt] or [quad_gantry_level]
  • Custom homing, leveling, or bed-scanning macros

Resolution:

  1. Ensure the probing depth for all probe actions is within the EDDY's usable range.
  2. Avoid multiple macros or configuration sections overriding the same height parameter.
  3. After modifications, save and restart Klipper, then re-run homing or leveling.
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Errors Eddy I2C STATUS/DATA error or Invalid read data​

These errors indicate abnormal communication or readings between the EDDY and the MCU.

Common causes:

  • Poor contact in the EDDY wiring, connector, or solder joints.
  • I2C cables are too long, poor quality, or run parallel to motor or heater wires causing interference.
  • I2C speed is too high, unstable with the current cable and environment.
  • Unstable probe power supply.

Resolution:

Power Off

Completely shut down the printer and disconnect the power supply before reconnecting EDDY cables, tidying wiring, or checking connectors. Do not plug or unplug sensors or touch terminals while the power is on.

  1. Power off, then reconnect the EDDY cable harness and check for loose terminals.
  2. Route the EDDY communication cables away from motor, heater, and heated bed wires.
  3. If using hardware I2C, try lowering the I2C rate. If still unstable, test software I2C.
  4. Prioritize cross-testing by replacing the ready-made cable, changing ports, or swapping the sensor. For electrical testing of exposed terminals, contact after-sales or a professional.
  5. After modifications, re-run homing or PROBE_EDDY_CURRENT_CALIBRATE.

Error Unable to obtain probe_eddy_current sensor readings​

This error indicates Klipper did not receive valid data from the EDDY sensor within the expected timeframe.

Common causes:

  • Sensor communication cable is disconnected or the bus/pin configuration is incorrect.
  • The probe is too far from the metal bed surface; readings are out of range.
  • reg_drive_current is not suitable; the sensor frequency range is insufficient.
  • Drive current calibration or Z height calibration has not been completed.

Resolution:

Power Off

Completely shut down the printer and disconnect the power supply before checking EDDY bus/pin wiring or replacing sensor cables. Do not plug or unplug sensors while the power is on.

  1. Power off, then confirm that the bus and pin configuration in [probe_eddy_current fly_eddy_probe] matches the actual wiring.
  2. Move the nozzle to the center of the heated bed, ensuring the EDDY is above the metal bed surface.
  3. Re-run LDC_CALIBRATE_DRIVE_CURRENT CHIP=fly_eddy_probe and SAVE_CONFIG.
  4. Re-run PROBE_EDDY_CURRENT_CALIBRATE CHIP=fly_eddy_probe.
  5. If the error only occurs during homing, continue adjusting reg_drive_current and z_offset as per the "Error During Homing" section above.

Abnormal TAP Mode Trigger​

When using EDDY's METHOD=tap, if probing stops prematurely, doesn't stop after contacting the bed surface, or results are significantly unstable, it is usually related to tap_threshold and the state of the nozzle/bed surface.

Detailed Guide: EDDY TAP Mode Debugging

Motion Risk

TAP testing brings the nozzle close to or in contact with the heated bed. Before execution, ensure the nozzle and bed surface are clean, keep hands and tools away from the motion area, and be ready for an emergency stop.

Troubleshooting Points:

  1. Ensure the nozzle and bed surface are clean; residual material on the nozzle directly affects TAP results.
  2. Before starting TAP, maintain a distance of a few millimeters between the nozzle and the bed; do not be too close or too far.
  3. If the probing stops without contacting the bed, tap_threshold might be too low; try increasing it.
  4. If the probing does not stop after contacting the bed, tap_threshold might be too high; stop immediately and decrease the threshold.
  5. After adjustment, re-run PROBE_EDDY_CURRENT_TAP_CALIBRATE. Once successful, run SAVE_CONFIG.

First Layer Instability Due to Thermal Drift​

EDDY is an eddy current sensor. Changes in bed temperature, nozzle temperature, sensor coil temperature, and the temperature of nearby metal parts can all affect measurement results. This often manifests as: calibration is normal when cold, but the first layer is too high or too low when hot.

Resolution:

  1. Preferably perform EDDY calibration at a temperature close to the actual printing temperature.
  2. Before printing, wait for the heated bed and nozzle temperatures to stabilize before homing, leveling, or scanning the bed.
  3. If the EDDY has a temperature sensor, configure [temperature_probe] and perform thermal drift compensation.
  4. For enclosed printers, perform fine calibration after the chamber temperature has stabilized.

Suggestions for Debugging z_offset​

In many debugging cases, setting the initial value of z_offset in [probe_eddy_current fly_eddy_probe] to 2.5 has helped many EDDY sensors reach a working state faster.

Note

2.5 is a starting point for debugging, not a universal fixed value or official default configuration. The optimal offset depends on the probe installation position, nozzle height, and machine structure. Always base it on actual calibration results.

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