Siemens SINUMERIK 840C Installation Instructions Manual page 961

12 Functional Descriptions 09.95
12.19.3 Interlocks and monitoring
IKA warning limit with axis compensation
When the compensatory/additional values of the output quantity are high, the machine may
make unexpected movements which are only partly limited by the monitoring functions. The
present output value is therefore checked against the limit set in NC MD 356* and, in the case
of limit violation, an axis-specific interface signal of the PLC is set (DB 32, DR0, bit 6). In the
same way, the permissible velocity for the compensation (NC MD 1148*) is checked for
violation. The value is displayed in DB 32, DR k, bit 5. As a result of this signal, the PLC can
then, for example, activate follow-up mode in order to stop the axis.
8 decades with sign can be specified as the maximum permissible setting for the output
quantity compensatory/additional values. With this setting, long traverse distances can be
generated on the machine when the IKA configuration is selected, deselected or changed.
The traversing ranges that occur as a result of temperature, leadscrew error and beam sag
compensation are in the range 0.01 to 0.2 mm.
An IKA warning limit has been provided to ensure that excessive IKA movements are not
caused unintentionally by incorrect inputs (protected by password). When this limit is violated,
the PLC can decide which measures should be taken. The velocity must be as high as
possible in order to minimize contour errors when the IKA executes large-scale
compensatory/additional movements. The axial machine data "IKA/TK velocity" (NC MD 1148*)
is used for this purpose and defines the velocity at which the compensatory/additional
movement is performed.
The output quantity axis completes any compensatory/additional movement it has started, even
if the RESET command is given. HW limit switches, EMERGENCY STOP, etc. interrupt the
additionally required movement.
The effective velocity of a motion results from the input quantity axis velocity, the (in some
cases) subordinate velocity of the output quantity and the required compensatory/additional
motion.
The alarm checks evaluate the speed setpoint which effectively results.
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SINUMERIK 840C (IA)