User Manual

Motion control is easy
10.6 Operation of motion control for S7-1200
Easy Book
Manual, 03/2014, A5E02486774-AF
245
Hardware limit switches
Hardware limit switches determine the maximum travel range of the axis. Hardware limit
switches are physical switching elements that must be connected to interrupt-capable inputs
of the CPU. Use only hardware limit switches that remain permanently switched after being
approached. This switching status may only be revoked after a return to the allowed travel
range.
Table 10- 36 Available inputs for hardware limits
Description
RPS
LIM-
LIM+
Built-in I/O
I0.0 - I1.5
SB I/O
I4.0 - I4.3
When the hardware limit switches are approached, the axis brakes to a standstill at the
configured emergency deceleration. The specified emergency deceleration must be
sufficient to reliably stop the axis before the mechanical stop. The following diagram
presents the behavior of the axis after it approaches the hardware limit switches.
①
The axis brakes to a standstill at the configured emergency deceleration.
②
Range in which the hardware limit switches signal the stats "approached".
A
[Velocity]
B
Allowed travel range
C
Distance
D
Mechanical stop
E
Lower hardware limit switch
F
Upper hardware limit switch