890 HEIDENHAIN Technical Manual MANUALplus 620
6.16.18 Braking the drives for an emergency stop and a power failure
The parameter object CfgServoMotor is not required for:
Virtual axes (MP_axisMode=Virtual)
Axes that are for display only (MP_axisMode=Display)
Analog axes (MP_axisHw=Analog)
In an emergency stop and power failure the axes and the spindle must be
braked as quickly as possible. If the braking energy cannot be drawn off quickly
enough, the DC-link voltage increases sharply. If, in unfavorable cases, the
maximum regenerative power of the inverter is exceeded, the inverter is
switched off and the axes and spindle(s) coast to a stop. A powerful braking
of the drives also puts a high strain on the mechanics of the machine. With
gantry axes a mechanical offset can occur between the master and slave axes.
Problems with non-regenerative inverters (with braking resistors) during
braking mostly arise if the inverter is switched off too early. The strain on the
mechanics during braking is reduced, but can also be influenced with braking
strategies.
Regenerative inverters usually do not develop problems if they are switched
off. As a rule, the mechanics of the machine must be taken into account.
During a power failure ("powerfail"), the "SH1B" signal at X51 to X60 is
maintained for 10 more seconds, in order to brake the spindle(s). At the same
time, the control tries to reset the PLC outputs.
Settings in the configuration editor MP number
Axes
ParameterSets
[Key name of the parameter set]
CfgServoMotor
motEmergencyStopRamp
motPbrMax
motPbrMaxAcFail
401306
401307
401308