Siemens SINUMERIK 840D Description Of Functions page 458

8 Application examples
8.4 Safe cams at the modulo limit
Fig. 8-8
The appropriate machine data settings are used to negate SN1+ and round-off
on the NCK side. To implement this, the two cam signals should be
parameterized to an NCK output
36988
36989 SAFE_CAM_MINUS_OUTPUT[0]
or a system variable ($A_INSI[1])
36988
36989
The minimum logic (Chapter 3.9.19) of the NCK safety channel is used for
multiple assignment to an output or a system variable. This includes the
rounding-off of the assigned signals.
This type of logic is not available in the form of parameter settings on the
PLC side. The negation on the NC side is not effective for the drive (PLC) side,
therefore the position detection has to be programmed as shown below:
UN
U
=
=
Position detection at At the modulo limit, the cams respond differently to the description in 1)
modulo limit with and because of the modulo correction.
The following positions are saved in the machine data:
without SPL
36936 SAFE_CAM_POS_PLUS[0] :
36937 SAFE_CAM_POS_MINUS[0] : 359.5 Degrees
36905 SAFE_MODULO_RANGE :
8-458
SINUMERIK 840D/SIMODRIVE 611 digital SINUMERIK Safety Integrated (FBSI) - Edition 11.03
89.5°
SN1+
SN1-
Negating a safe cam signal to generate a pulse
SAFE_CAM_PLUS_OUTPUT[0]
SAFE_CAM_PLUS_OUTPUT[0]
SAFE_CAM_MINUS_OUTPUT[0]
DB3x.DBX109.0 // SN1+
DB3x.DBX109.1 // SN1-
M1.0 // Position detection 90° in
// marker 1.0
DB18.DBX54.0 // $A_INSIP[1]
// Position detection 90°
0° 90.5°
SN1+
inverted
SN1-
Modulo
correction
Position detection
&
90 degrees
81040101
01040101
84010101
04010101
0.5 Degrees
360 Degrees
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11.03