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

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7.2.11

Functionality of the SPL input/output data

The functionality of the SPL input/output data is exclusively defined by the user
(machinery construction OEM) within the scope of the PROFIsafe 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 the PLC and NCK use identical F net data for the two--channel gener-
ation of a PROFIsafe telegram, the SPL output data are interchanged alternating,
between the two channels (PLC: $A_OUTSEP and NCK: $A_OUTSE) in each
PROFIsafe clock cycle and before sending, are AND'ed with one another. For
safety reasons, this is the reason that the user must select the functionality of SPL
input/output data so that the value "0" corresponds to the safe state of the functio-
nality represented by this data. Only then can it be ensured that the corresponding
function is only activated at the F slave output if the function has actually been acti-
vated in both SPL programs (PLC--SPL and NCK--SPL).
Warning
!
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.
As a result of the synchronization of the SPL output data described above, it can-
not be ensured that when several SPL output data are changed simultaneously --
taking into account in the SPL program -- that these are also transferred con-
sistently (in time) in the PROFIsafe telegram. 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:
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:
Output value
Possible intermediate values
Final value
© Siemens AG 2015 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
NCK--SPL AND PLC--SPL
101 & 101
110 & 101
110 & 110
Connecting Sensors/Actuators
7.2 Connecting I/O via PROFIsafe
= PROFIsafe telegram
= 101
= 100
= 110
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