July 2013 6.11 Monitoring functions 933
Axis releases At the same time HEIDENHAIN recommends using the axis-specific "axis
releases" of the CC through the configuration in MP4132.x.
On controls with HSCI but without functional safety (FS), a pure axis enable,
which up to now has been realized over I32, can only be realized through the
function of the former X150. However, a CC 61xx does not have an X150
connector for axis-specific or axis-group-specific drive enabling.
But instead, you can now enter in machine parameters MP4132.0 to
MP4132.7 eight numbers of those PLC inputs that simulate the inputs of
X150. If one of these PLC inputs is switched off, the associated drives are
decelerated on the provided braking ramp (usually at the limit of current). Over
PLC module 9161 you have to switch off the axes of the affected axis groups.
To do so, you can use PLC module 9157 to scan the corresponding PLC inputs.
MP2040.0 to MP2040.7 continue to be used for the assignment of axes to
individual axis groups.
If the corresponding PLC inputs are switched off, the NC
transmits the nominal speed value "null", braking the drives on the intended
braking ramp (usually at the limit of current)
detects the standstill of the drives after braking and switches off the pulses
of the power stage over the PWM interface (-STO.B.x).
Machine parameter MP2173.x serves to monitor the braking of the drives. The
monitoring time for the braking process is defined in MP2173.x. After the
monitoring time has expired, the control checks whether the servo drive is at
a standstill. If this is not the case, the control assumes that a serious error has
occurred and switches off the pulses of the power stages via -STO.B.x (signal
to PWM cable). This ensures that, after a request to switch off the servo drives
(e.g. emergency stop, X150, PLC or alarm), the pulses are safely switched off
(via -STO.B.x) at the latest after the time specified in MP2173.x expires. If the
standstill is detected right before the time defined in MP2173.x expires, the
active braking process is continued and the pulses are not switched off until
after the overlap time.
The time for switching off the pulses (entry in MP2173.x) must be greater than
the maximum possible braking time of the axis/spindle that can occur through
electrical braking. Especially for axes/spindles without mechanical braking,
you must ensure that the pulses are not switched off until after the maximum
possible braking time for the axis/spindle that can occur through electrical
braking. Non-decelerated axes/spindles coast to a stop after pulse switch-off.
In the worst case, this can cause damage to the machine. Specific operating
conditions of the machine, such as maximum feed rate, overload on the axes,
etc., must also be taken into account.
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