Functionality Of The Spl Input/Output Data - Siemens SINUMERIK 840D sl Function Manual

The evaluation of the status signals of the SPL connections and changing the system
responses in the case of an error must, if necessary, be additionally programmed in the SPL.
Inverting status signals
Depending on the application, the user must invert the status signals of an F_SENDDP-/
F_RECVDP connection (e.g. $A_FSDP_ERROR[1...n], $A_FSDP_SUBS_ON[1...n],
$A_FRDP_ERROR[1...n], $A_FRDP_SUBS_ON[1...n], $A_FRDP_SENDMODE) when
further processing in the SPL. This is done in order to ensure a safe state in the case of
incorrect behavior/response of the PLC or NCK.
Example:
If $A_FRDP_SENDMODE is to be output as safety-related signal from the SPL to PROFIsafe,
then this signal must first be inverted. This is done in order that the failsafe value "0" also
corresponds to the safe state, i.e. it has the significance "deactivated safety mode".
8.4.15

Functionality of the SPL input/output data

Only the user (machinery construction OEM) defines the functionality of the SPL input/output
data within the scope of the F_DP communication.
The SPL programs of NCK-SPL and PLC-SPL are not executed synchronously (from a time
perspective). Brief differences in the output data of the two SPL programs (NCK: $A_OUTSE,
PLC: $A_OUTSEP) can occur due to the runtime differences in the SPL programs.
In order that PLC and NCK-F_SENDDP use identical F-net data when generating an F-
telegram through two channels, the SPL output data are exchanged alternating between the
two channels (PLC: $A_OUTSEP and NCK: $A_OUTSE) in each F_DP clock cycle and are
then AND'ed before the sender. For safety reasons, this is the reason that the user (machine
OEM) must select the functionality of SPL input/output data so that the value "0" corresponds
to the safe state of the functionality represented by this data. Only then can it be absolutely
ensured that the appropriate function is only activated on CPU2 (F_RECVDP) if the function
is activated in both SPL programs (PLC-SPL and NCK-SPL) of CPU1 (F_SENDDP).
Safe state of SPL input/output data
For safety reasons, this is the reason that the functionality of an SPL input or output data is
selected so that the value "0" corresponds to the safe state of the functionality represented
by this data.
The synchronization of the SPL output data described above ensures that if it is intended to
simultaneously change several SPL output data in the SPL program, then these are also
consistently transferred (in time) in the F-net data telegram of the F_SENDDP. If, in a user
application, several SPL output data are interpreted as a contiguous bit pattern, it must
therefore be taken into account that intermediate values can briefly occur.
Example:
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
8.4 Safety-related CPU-CPU communication (F_DP communication)
WARNING
WARNING
Connecting sensors and actuators
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