Siemens SINUMERIK Series

A4: Digital and analog NCK I/Os for SINUMERIK 840D sl
1.2 Access via PLC
Extended Functions
Function Manual, 03/2013, 6FC5397-1BP40-3BA1
31
1.2.3 NCK digital inputs/outputs
1.2.3.1 NCK digital inputs
Function
The workpiece-machining program sequence can be controlled by external signals via digital
NCK inputs.
The signal state of digital input <n> can be scanned directly in the part program using
system variable $A_IN [<n>].
The signal state at the hardware input can be changed from the PLC user program.
Applications
Digital NCK inputs are used, for example, for the following NC functions:
● Delete distance-to-go with positioning axes
● Fast program branching at the end of block
● Programmed read-in disable
● Several feedrates in one block
References:
Function Manual, Synchronized Actions
Signal flow
The following figure illustrates the signal flow for the digital NCK inputs.
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