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

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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.

$A_PLCSIOUT[1...32]

$A_PLCSIIN[1...32]

System variables $A_PLCSIOUT[1...32] and $A_PLCSIIN[1...32] 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".

SINUMERIK 840D sl/SINAMICS S120 SINUMERIK Safety Integrated (FBSI sl) – 05.2008 Edition

7.3 Safe programmable logic (SPL)

Connecting Sensors/Actuators

32 bits from the NCK to PLC

32 bits from the PLC to NCK

Sinamics s120