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

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7.5.12 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.
In order to be able to exchange single--channel SI--specific signals between the
NCK and PLC in a dedicated data area, a corresponding communication interface
exists between these components. The meaning of the individual bits in this inter-
face are defined by the user.
NCK
$A_PLCSIOUT[1...96]
$A_PLCSIIN[1...96]
Boundary conditions
System variables $A_PLCSIOUT[1...96] and $A_PLCSIIN[1...96] are protected so
that they cannot be accessed from other programs, except the NCK--SPL program
(SAFE.SPF). A corresponding programming command is rejected with the alarm
17070 "Channel %1 block %2 Data write--protected".
© Siemens AG 2015 All Rights Reserved
SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) - - 10.2015 Edition
7.5 Safe programmable logic (SPL)
PLC
DB18.DBB128--131,
DB18.DBB432--439
DB18.DBB132--135,
DB18.DBB440--447
Connecting Sensors/Actuators
96 bits from the NCK to PLC
96 bits from the PLC to NCK
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