Siemens SINUMERIK 840Di Function Manual page 1932

Detailed Description
2.2 Axis monitoring, protection zones (A3)
DB31, ...
DBX12.0 - DBX12.1 Hardware limit switches plus and minus
Edge evaluation: no
Signal state 1 or A switch can be mounted at each end of the travel range of a machine axis which will cause a
edge change signal "hardware limit switch plus or minus" to be signaled to the NC via the PLC if it is actuated.
0 → 1
If the signal is recognized as set, alarm 021614 "hardware limit switch + or -" is output and the axis
is decelerated immediately.
The braking/deceleration type is defined using the machine data:
MD36600 $MA_BRAKE_MODE_CHOICE (braking behavior at the hardware limit switch)
If the controller enable is withdrawn at the same time as the "hardware limit switch" signal, then the
axis responds as described in Chapter A2 ("various interface signals").
Signal state 0 or Normal condition - a hardware limit switch has not been actuated.
edge change
1 → 0
Corresponding to .... MD36600 $MA_BRAKE_MODE_CHOICE (deceleration behavior when the hardware limit switch
responds)
DB31, ...
DBX12.2 - DBX12.3 2nd software limit switch plus or minus
Edge evaluation: no
Signal state 1 or 2nd software limit switch for the plus and minus directions is effective.
edge change
1st software limit switch for the plus and minus directions is not effective.
0 → 1
In addition to the 1st software limit switches (plus and minus), the 2nd software limit switches (plus
and minus) can be activated using these interface signals.
The position is defined using machine data:
MD36130 $MA_POS_LIMIT_PLUS2 (2nd software limit switch plus)
and
MD36120 $MA_POS_LIMIT_MINUS2 (2nd software limit switch minus).
Signal state 0 or 1st software limit switch for the plus and minus directions is effective.
edge change
2nd software limit switch for the plus and minus directions is not effective.
1 → 0
Corresponding to .... MD36110 $MA_POS_LIMIT_PLUS (1st software limit switch plus)
MD36130 $MA_POS_LIMIT_PLUS2 (2nd software limit switch plus)
MD36100 $MA_POS_LIMIT_MINUS (1st software limit switch minus)
MD36120 $MA_POS_LIMIT_MINUS2 (2nd software limit switch minus)
2-68
Signal(s) updated: cyclic
Signal(s) updated: cyclic
NC/PLC Interface Signals (Z1)
Function Manual, 08/2005 Edition, 6FC5397-0BP10-0BA0