Direct Communications Between Nck And Plc-Spl - Siemens SINUMERIK 840D sl Function Manual

Data area/status
SPL_DATA
The useful (net) data for the PLC-SPL is contained in the SPL_DATA structure. The net data
area is sub-divided into internal inputs/outputs and marker areas and external inputs/outputs
that correspond to the hardware I/O.
With the appropriate parameterization for external inputs/outputs, the basic program transfers
the input image of the I/Os to the external inputs in DB18 and from the external outputs in
DB18 to the output.
SPL_DELTA
The SPL_DELTA area is used for diagnostics. A signal with the status TRUE in this area means
that the signal is different in the NCK and PLC at this bit position.
CMDSI
Signal CMDSI can be used to extend the timeout value in the crosswise SPL data comparison
by a factor of 10. This extension is used for long forced checking procedure pulses or single-
channel test stop logic functions.
STATSI
A value not equal to 0 means that an error has occurred in the crosswise data comparison.
LEVELSI
The LEVELSI signal is used for diagnostics, and provides information as to how many signals
are presently active with different signal levels.
COMM_TO
If communication between NCK and PLC regarding the SPL-CDC is interrupted, then the PLC
is switched into the STOP state with a delay of 5 s. Status signal DB18.DBB119, bit 5 is used
to inform the SPL programmer that the 5 s timer was started. This means that it is possible to
initiate system-specific actions before the PLC goes into the stop condition.
SPL status signals for SPL_STATUS (DB18.DBB136)
For a detailed description, refer to Chapter "PLC data block (DB18) (Page 486)"
8.5.12

Direct communications between NCK and PLC-SPL

In SPL applications, a certain degree of single-channel communications between the two SPLs
(NCK and PLC) is always required in addition to safety-related switching elements being
connected through two channels. Testing external stops and the Emergency Stop
acknowledgment are typical applications.
Safety Integrated
Function Manual, 12/2017, 6FC5397-4BP40-6BA1
Connecting sensors and actuators
8.5 Safe programmable logic
289