12 Functional Descriptions 08.96
12.31 Dynamic SW limit switches for following axes
12.31 Dynamic SW limit switches for following axes12.31.1 Corresponding data
• MD 560*, bit 1 Dyn. SW limit switches for following axes
• MD 560*, bit 5 Software limit switches active
• MD 3932* Deadtime compensation for dyn. SW limit switches
• MD 3936* Minimum reduction factor for dyn. SW limit switches
• DB32 DR[K], bit 3 Axis is in reduction range
• DB32 DR[K+1], bit 2 Dynamic SW limit switch monitoring passive
• DB10 ... 15, DR0. bit 0 Path speed of channel not reduced
General
• Behaviour of following axis without monitoring
If a gear interpolation is active in the SINUMERIK 840C, then the software limit switch for
the following axis is monitored only when the actual position is exceeded. If the following
axis crosses the limit switch, a servo alarm (148* to 152*) is output and the axis grouping
braked. In this case, the axis travels a long distance passed the limit switch depending on
its speed.
• Behaviour of following axis with monitoring
The purpose of the function is to monitor the position of the following axis continuously
and, if required, to reduce the path speed of the channels in the mode group such that the
following axis travels only a short distance past the switch. The axis grouping is not
separated.
12.31.2 Description of function
• Sequence
The SW limit switches for following axes are monitored only if
– MD 560*, bit 1 = 1 "Dyn. SW limit switches for following axes"
– MD 560*, bit 5 = 1 "Software limit switches active"
– Axis is referenced
– Axis is following axis when gear interpolation is active
– C axis in C axis mode, not spindle mode
– PLC signal to axis, bit 2 = 0: "Dynamic SW limit switch monitoring passive"
– PLC signal to channel, bit 0 = 0: "Path speed of channel not reduced"
The axis-specific PLC signal "Dynamic SW limit switch monitoring passive" allows the user
to switch the monitoring function on and off. The signal to channel "Path speed of channel
not reduced" determines whether the path speed of the channel is reduced.
• Reduction range
A braking path is calculated for each following axis from the max. velocity V
max
and the
max. acceleration A
max
in the machine data. This braking path represents an area in front
of the software limit switches that is referred to as "reduction range" below. The reduction
range is always re-calculated after the machine data have been changed.
Reduction range (V
max
* V
max
) / 2 * A
max
12–312
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SINUMERIK 840C (IA)