Safe Software Cams (4 Cam Pairs) - Siemens SINUMERIK 840D sl Function Manual

7.8.1

Safe software cams (4 cam pairs)

Note
For more than four cam pairs, then the "Safe Cam Track" function must be used (see Chapter
"Safe Cam Track (Page 162)").
Description
There are 4 pairs of cams (SN1, SN2, SN3, SN4) available for each axis. Each cam pair
consists of a plus cam (SN1+, SN2+, SN3+, SN4+) and a minus cam (SN1-, SN2-, SN3-,
SN4-). Each cam signal can be individually enabled and configured via machine data. The
cam signals are output via SGAs.
Preconditions
The following prerequisites must be fulfilled for the "safe software cams" function:
● The axis/axes must have been safely referenced (user agreement)
● The Safe Cams must be configured:
The required cams are enabled using machine data
For 840D sl:
MD36901 $MA_SAFE_FUNCTION_ENABLE, bits 8...15 and parameters
For SINAMICS S120:
p9501 SI Motion enable safety functions, bits 8...15
SGA assignment is defined using machine data
For 840D sl:
MD36988 $MA_SAFE_CAM_PLUS_OUTPUT[n] and
MD36989 $MA_SAFE_CAM_MINUS_OUTPUT[n]
Defining the cam positions
The cam positions are defined in the following machine data/parameters:
For 840D sl:
MD36936 $MA_SAFE_CAM_POS_PLUS[0...3]
MD36937 $MA_SAFE_CAM_POS_MINUS[0...3]
For SINAMICS S120:
p9536[n] SI Motion SCA (SN) plus cam position (Control Unit)
p9537[n] SI Motion SCA (SN) minus cam position (Control Unit)
Special case for SN
If the axis is positioned precisely at the parameterized cam position, the cam signals may have
different states owing to system-related variations in the actual values between the two
monitoring channels. This must be taken into account when safely processing the cam signals,
e.g. by filtering the different signal states by means of a logic circuit (see "Synchronizing cam
signals").
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Safety functions integrated in the system/drive
7.8 Safety software cams and safety cam track (SN)
159