Functional Secondary Conditions - Siemens SINUMERIK 840D sl Function Manual

Three SPL output data are considered to be contiguous. The value is changed from 101 to
110 in both SPL programs (NCK-SPL and PLC-SPL). Values transferred in the PROFIsafe
telegram:
Possible intermedi‐
Runtime differences
Due to runtime differences in the NCK-SPL and PLC-SPL, it cannot be guaranteed that when
several SPL output data are simultaneously changed that these are then consistently
transferred in the PROFIsafe telegram.
8.2.12

Functional secondary conditions

When connecting via SPL I/O using
conditions and constraints must be taken into consideration when configuring and
programming:
● Faults/errors in the PROFIsafe input devices (e.g. input signals that differ from one another)
cause the associated SPL input signals ($A_INSE(P)) to be deleted (cleared). This initiates
a STOP D/E.
● The transfer of the external SPL input signals in the DB18 interface for the $A_INSEP
variables is realized inside the system. Only one signal state for both SPL channels is
transferred to the master from the PROFIsafe input peripherals.
● The external SPL output signals of the DB18 interface ($A_OUTSEP variables) are
transferred within the system to the relevant PROFIsafe output modules. A signal state is
transferred to the output modules via PROFIsafe.
● It may be necessary to use single-channel signals (signals that are present only in the PLC
or only in the NCK) to change over external SPL outputs (e.g. brake control). These single-
channel signals must also be made available to the other program channel to align the logic
and program synchronously. Direct communications between the NCK and PLC-SPL via
DB18 is a good way to achieve this.
● In each PROFIsafe cycle, the PROFIsafe layer generates a PROFIsafe telegram with the
logically AND'ed SPL output data as F-net (useful) data.
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
NCK-
SPL
Output value 101
110
ate value
Final value 110
WARNING
AND PLC-SPL =
& 101 =
101
& =
& 110 =
one safety-related bus (PROFIsafe), several secondary
Connecting sensors and actuators
8.2 Connecting I/O via PROFIsafe
PROFIsafe telegram
101
100
110
209