Siemens SINUMERIK 840D Description Of Functions page 468

8 Application examples
8.6 Direction detection when retracting from SE
Implementation in the The interface signal for the hardware limit switch- (DBX12.0) should be
PLC supplied with the inverted cam signal of SNx- and the interface signal for the
hardware limit switch+ (DBX12.1) should be supplied with the cam signal of
SN+. It should be noted that the SGA for the cam signal is not available until
the drive has powered up.
Example (when using the 1st cam pair)
U
L
SE
UN
SPB NOSN
UN
=
U
=
NOSN: NOP 0
This logic can be used to implement the required interlocking function when
retracting.
8-468
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
DB10.DBX108.5 // Drives in cyclic
// mode
S5T#50ms // Transition period to avoid
// timing problems
T100 // Timer as
// input delay
T100 // While the time has still not
// expired, the HW limit switch
// signals are not supplied
DB<axis>.DBX109.0 // SN1-
DB<axis>.DBX12.0 // Hardware limit switch -
DB<axis>.DBX109.1 // SN1-
DB<axis>.DBX12.1 // Hardware limit switch +
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11.03