Software Limit Switch - Siemens SIMATIC S7-1500 Function Manual

3.17.3

Software limit switch

The operating range of the axis is limited with software limit switches. Relative to the
traversing range, always position the software limit switches within the hardware limit
switches. Since the positions of the software limit switches can be flexibly configured, the
operating range of the axis can be individually adapted in accordance with the current
velocity profile.
Software limit switches are only effective when there is a valid actual value after homing the
technology object. The monitoring of the software limit switches is relative to the setpoint.
Modulo enabled
With modulo enabled, the modulo position is monitored.
The software limit switches are enabled or disabled using the tags in the technology data
block. If the positions of both software limit switches are outside the modulo range, then the
monitoring has no effect. It is not checked, whether the positions of the software limit
switches are within the modulo range.
Approaching the software limit switches
At the beginning of a positioning motion, it is not checked, whether the software limit
switches will be approached by approaching the specified target position.
If the software limit switches are approached, then technology alarm 533 is output, and the
axis is stopped with the maximum dynamic values (alarm response: Stop with maximum
dynamic values). The technology object remains enabled.
Overshooting the software limit switches
If a software limit switch is overshot, technology alarm 534 is output, and the technology
object is disabled (alarm response: remove enable).
Retracting
Proceed as follows to retract the axis after violation of the software limit switch:
1. Acknowledge the technology alarm.
2. Move the axis in the free travel direction, until the software limit switch is exited.
S7-1500 Motion Control V13 Update 3
Function Manual, 07/2014, A5E03879256-AC
If you move opposite to the free travel direction before exiting the software limit switch,
then the monitor with be triggered again.
3.17 Traversing range limitation
Basics
67