Siemens SINUMERIK 840D sl Function Manual page 36

Digital and analog NCK I/Os (A4)
1.2 NCK I/O via PLC
Setting mask
Furthermore, a PLC setting for each output can determine whether the current NCK value
(e.g., as specified by the NC part program) or the PLC value specified via the setting mask
(DB10, DBB7 or DBB133 ...) should be sent to the hardware output (see fig.).
The following routine has to be carried out to define the PLC value:
1. The output in question must be preset with the required signal state at the PLC interface
DB10, DBB6 (PLC setting value for digital NCK outputs).
2. The setting mask must be set to "1" for the output in question.
Unlike the overwrite mask, the NCK value is not lost when a value is set in the setting mask.
As soon as the PLC sets "0" in the setting mask, the NCK value becomes active again.
Note
The same setting value (DB10, DBB6) is used at the PLC interface for the overwrite and
setting masks. Therefore, an identical output signal state is the result if the signal state is
changed simultaneously in the overwrite and setting maska.
Read setpoint
The current NCK value of the digital outputs can be read by the PLC user program:
DB10, DBB64 or DBB186 ... (setpoint for digital NCK outputs)
Please note that this setpoint ignores disabling and the PLC setting mask. Therefore, the
setpoint can differ from the actual signal state at the hardware output (see fig.).
RESET/end of program
At the end of the program or on RESET, a specific default value can be assigned by the PLC
user program to every digital output in accordance with requirements, using the overwrite
mask, setting mask or disable signal.
POWER ON
After POWER ON, the digital outputs are set to "0" in a defined manner. This can be
overwritten from the PLC user program according to the specific application using the masks
described above.
Digital NCK outputs without hardware
If digital NCK outputs, as defined in the following general machine data, are written by the
part program, but are not available as hardware, no alarm is output. The NCK value can be
read by the PLC (IS "setpoint ..."). :
MD10360 $MN_FASTIO_DIG_NUM_OUTPUTS
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Function Manual, 01/2008, 6FC5397-1BP10-3BA0
Extended Functions