Nck Digital Outputs - Siemens SINUMERIK 840D sl Function Manual

1.2.2.2

NCK digital outputs

Number
The available digital NCK outputs can be defined (in groups of eight) using the following
general machine data (number of active digital NCK output bytes):
MD10360 $MN_FASTIO_DIG_NUM_OUTPUTS
Function
The digital NCK outputs provide the option of outputting important switching commands at
high speed as a function of the program processing status.
The signal state of digital output [n] can be set or read again directly in the part program
using system variable $A_OUT[n].
There are also several ways of changing this set signal state via the PLC (see fig.).
Disable output
The PLC user program is capable of disabling the digital NCK outputs individually with
interface signal
DB10, DBB4 or DBB130 ... (disable digital NCK outputs).
In this case, the "0" signal is output at the hardware output (see fig.).
Overwrite mask
Every output that can be set by the NC part program can be overwritten from the PLC using
the overwrite mask. The previous NCK value is then lost (see fig.).
The following routine has to be carried out to overwrite the NCK value from the PLC:
1. The relevant PLC interface output has to be set to the required signal status. :
2. The setting value becomes the new NCK value when the overwrite mask for the relevant
Extended Functions
Function Manual, 01/2008, 6FC5397-1BP10-3BA0
DB10 DBB6 or DBB132 ... (Setting value by PLC of digital NCK outputs)
output (DB10, DBB5, or DBB131 ...) is activated (signal transition 0 → 1). This value
remains operative until a new NCK value is programmed (by the PLC or from the NC part
program).
Digital and analog NCK I/Os (A4)
1.2 NCK I/O via PLC
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