Siemens SINAMICS S120 Function Manual page 513

Software limit switch
The connector inputs p2578 (software limit switch minus) and p2579 (software limit switch
plus) limit the position setpoint if the following prerequisites are fulfilled:
● The software limit switches are activated (p2582 = "1")
● The reference point is set (r2684.11 = 1)
● The modulo correction is not active (p2577 = "0")
The connector inputs are, in the factory setting, linked to the connector output p2580
(software limit switch minus) and p2581 (software limit switch plus).
STOP cam
A traversing range can, on the one hand, be limited per software using the software limit
switches and on the other hand, the traversing range can be limited per hardware. In this
case, the functionality of the STOP cam (hardware limit switch) is used. The function of the
STOP cams is activated by the 1 signal on the binector input p2568 (activation of STOP
cams).
Once enabled, the activity of binector inputs p2569 (STOP cam, minus) and p2570 (STOP
cam, plus) is checked. These are low active; this means if a 0 signal is present at binector
input p2569 or p2570, then these are active.
When a STOP cam (p2569 or p2570) is active, the current motion is stopped with OFF3 and
the appropriate status bit r2684.13 (STOP cam minus active) or r2684.14 (STOP cam plus
active) is set.
When an axis has approached a STOP cam, only motion that allows the axis to move away
from the cam is permitted (if both STOP cams are actuated, then no motion is possible).
When the STOP cam is exited, this is identified by the 0/1 edge in the permitted traversing
direction which means that the corresponding status bits (r2684.13 or r2684.14) are reset.
Drive functions
Function Manual, 11/2017, 6SL3097-4AB00-0BP5
Function modules
8.8 Basic positioner
513