As a general rule of thumb, FANUC determines the standard moving deviation using the feed rate and the position loop gain (Parameter 1825). The basic theoretical deviation ( ) can be calculated as:

If the motor drops immediately upon powering down the servos, the mechanical brake is not engaging. 3. Check Motor/Servo Drive (Power Off)

: Verify the axis is properly lubricated; dry ways can cause enough friction to force an axis out of position.

Use FANUC’s #8000 series system variables to query the current search status dynamically—though not directly settable via macro, you can detect search failures and retry with a higher range.

If you are getting an SV 0411 alarm and suspect Parameter 1829 needs attention, follow this systematic approach: Step 1: Check the Diagnosis Screen Before changing parameters, look at the actual error. Press the function key on your FANUC MDI panel. Press the [DIAGN_S] (Diagnosis) softkey. Look up Diagnostic Number 300 (Position Deviation).

To isolate mechanical issues from electrical faults, technicians often temporarily increase the value of Parameter 1829.

Incorrectly configured servo parameters (such as loop gain settings in Parameter 1825 or load inertia settings in Parameter 2021) can affect how precisely an axis holds position, potentially leading to overshoot that triggers Parameter 1829.

You must have password/access level to FANUC’s parameter writing enable. Typically, this requires setting PWE (Parameter Write Enable) to "1" or having a maintenance key.

The relationship between these parameters is interconnected. For example, excessive following error during movement (Parameter 1828 violation) may lead to overshoot after stopping, potentially triggering Parameter 1829 as well. Conversely, improper loop gain settings (Parameter 1825) can cause instability that manifests as stopping errors.