231-A210

Access brake machine parameters

Press MOD, enter access code, select 'Machine Parameters'. Navigate to MP1010 series for the affected axis. Check MP1010.0 (brake active), MP1010.1 (brake delay time), MP1010.2 (brake release delay), and MP1010.3 (brake monitoring time).

Typical brake engagement delays range from 50-150ms for electromagnetic brakes. If monitoring time is shorter than actual brake response, this alarm will trigger.

Measure actual brake response time

Use MOD 4 8 (Scope function) to capture the brake output signal and monitor servo following error simultaneously. Command a controlled axis movement and observe the time between brake release command and actual axis motion capability.

Add 20-30% margin to measured brake response time when setting MP1010 parameters to account for temperature variations and brake aging.

Adjust brake timing parameters

Increase MP1010.1 (engagement delay) or MP1010.2 (release delay) based on measured values. Ensure MP1010.3 (monitoring window) is set appropriately for the control step that failed. Save parameters and cycle power to ensure changes take effect.

Insufficient brake engagement delay before servo disable can cause axis drift. Insufficient release delay can cause servo faults during motion start.

Test brake control sequence

Manually enable/disable the axis drive using the manual control panel while monitoring the brake output in the PLC status display or using Scope. Verify alarm no longer occurs and axis holds position reliably when drive is disabled.

Check brake feedback configuration

Review machine parameters for brake feedback input assignment. Check MP1010.4 or related parameters that define which PLC input monitors brake status. Verify if feedback monitoring is enabled for this axis.

Not all machines use brake feedback. If MP1010.4 is set to a value other than 0 or -1, feedback monitoring is likely active.

Monitor PLC inputs for brake feedback

Access PLC program status (MOD PLC function) and identify the input assigned to brake feedback. Manually energize and de-energize the brake (with axis locked) and verify the PLC input changes state correspondingly.

Only test with axis mechanically secured or in a safe position to prevent movement if brake releases.

Inspect brake feedback sensor/contact

Check wiring and connections to the brake feedback sensor (typically a reed switch, proximity sensor, or auxiliary contact on brake relay). Test sensor functionality with multimeter or by checking signal at control input terminals.

Brake auxiliary contacts can fail from switching wear. Replace if contact resistance exceeds 1 ohm or shows intermittent behavior.

Verify PLC logic for brake control

If using structured PLC program, review the brake control module for the affected axis. Check that feedback signal is properly integrated into the control logic and timeout values match machine parameters.

Standard Heidenhain PLC template modules for brake control are typically named similar to 'BR_CTRL_AX' or axis-specific brake functions.

Identify brake output signal assignment

Check machine documentation or MP1010 parameters to determine which physical output controls the brake. This may be a dedicated brake output from the drive (CC/MC), a PLC output from the TNC, or an output from an external I/O module.

On integrated Heidenhain MC/CC controls, brake outputs are typically hardwired from the axis module. On modular systems, check PLC output assignment in MP7210.x series.

Test brake output signal at control

Use PLC status display or force PLC outputs (MOD PLC) to manually activate the brake output. Measure voltage at the output terminal on the control to verify the control is switching properly (typically 24VDC).

Use caution when forcing outputs. Ensure axis cannot move unexpectedly. Follow lockout/tagout procedures.