10620

Check Current NC Block

In SINUMERIK Operate, navigate to Program > Editor and examine the NC block where alarm occurred. Look for missing F-word before any G01/G02/G03 commands.

Use the cursor position indicator in the NC editor to identify the exact block that triggered the alarm.

Verify Modal Feedrate Status

Press Machine > Diagnostics > Service > Variables and check $AA_MODAL[F] to see current modal feedrate value. Zero indicates no feedrate is active.

Modal feedrate is lost after M02/M30 or when switching between feed modes.

Add Valid F-Word

Edit the NC program to include appropriate F-word (e.g., F1000 for mm/min) before the motion command. Ensure F-value matches units set in MD20150 (AXCONF_MACHAX_USED).

Always verify feedrate units - G94 (mm/min) vs G95 (mm/rev) to prevent excessive speeds.

Check Override Panel Settings

Verify the feedrate override rotary switch on HMI is not at 0% position. Check Machine > Manual > Override display for current percentage values.

Some machines have separate feed and rapid override controls - check both.

Verify Override Machine Data

Access Commissioning > Machine Data and check MD20200 (FEEDRATE_DEF_MASK) and MD20210 (OVERRIDE_FACTOR_LIMIT) for proper override behavior configuration.

Modifying machine data requires appropriate access level and may affect machine safety.

Reset Override to Normal

Set feedrate override to 100% and test program execution. If using external override signals, check PLC interface FB2 (override values) in Program > PLC.

External override signals from PLC can override panel settings - check DB21 DBX override bits.

Identify Variable Feedrate Programming

In Program > Editor, search for F= expressions or F[R-parameter] usage. Note which variables are used for feedrate calculation.

Use Find function (Ctrl+F) to search for 'F=' or 'F[' patterns in the NC program.

Check Variable Values

Navigate to Program > Variables > R-Parameters and verify current values of variables used in feedrate calculation. Zero values will cause alarm 10620.

Uninitialized R-parameters default to zero and will cause feedrate errors.

Validate Calculation Logic

Review arithmetic expressions in F-word programming for division by zero or logic errors. Add parameter initialization at program start if needed.

Use DEF statements at program beginning to initialize all R-parameters with safe default values.

Check Feed Mode Transitions

Review NC program for G94 (feed per minute) and G95 (feed per revolution) switches. Modal feedrate may be lost during these transitions depending on MD20150 settings.

Some SINUMERIK configurations clear modal feedrate when switching between G94 and G95 modes.

Verify Coordinate System Changes

Check for G54-G59 or G500/G53 usage that might affect modal conditions. Navigate to Machine > Diagnostics > NC > Channel State to see current modal states.

Absolute coordinate programming (G53) can affect modal feedrate behavior.

Add Feedrate After Mode Changes

Modify NC program to explicitly program F-word after any G94/G95 switches or coordinate system changes to ensure valid feedrate is always active.

Create a standard subroutine for mode initialization that includes feedrate establishment.

Verify G95 Mode Usage

Check if NC program uses G95 (feed per revolution) by examining modal states in Machine > Diagnostics > NC > Channel State or reviewing G-code.

G95 mode requires active spindle rotation to calculate effective feedrate.

Check Spindle Speed Status

Verify spindle is programmed and running by checking Machine > Diagnostics > Drives for spindle speed value. Zero RPM with G95 causes zero feedrate.

Ensure spindle direction (M03/M04) is programmed before G95 feed moves.

Program Spindle Speed or Switch to G94

Add appropriate S-word and M03/M04 before G95 moves, or change to G94 mode with mm/min feedrate programming if spindle operation is not required.

Use SPOS for spindle positioning if rotation is not needed but G95 mode is required.