Siemens SINUMERIK Series Function Manual page 42

A4: Digital and analog NCK I/Os for SINUMERIK 840D sl
1.2 Access via PLC
Weighting factor
The weighting factor can be used to adapt each individual NCK output to the various DA
converters (depending on the I/O module ) for programming in the part program:
MD10330 $MN_FASTIO_ANA_OUTPUT_WEIGHT[<n>]
In this machine data, it is necessary to enter the value x that is to cause the analog output
<n> to be set to the maximum value or the value 32767 to be set for this output in the PLC
interface, if $A_OUTA[n] = x is programmed. The value set with system variable
$A_OUTA[<n>] then generates the corresponding voltage value at the analog output in
millivolts.
Example:
Analog-value range is 10 V (maximum modulation);
MD10330 $MN_FASTIO_ANA_OUTPUT_WEIGHT[<n>] = 10000 (default value)
$A_OUTA[1] = 9500; 9.5 V is output at analog NCK output 1
$A_OUTA[3] = -4120; -4.12 V is output at analog NCK output 3
Note
Application for analog NCK outputs without hardware:
With a weighting factor of 32767, the digitized analog values for part program and PLC
access are identical. In this way, it is possible to use the associated output word for 1:1
communication between the part program and the PLC.
Binary analog-value display
See "Representation of the NCK analog input/output values (Page 43)".
Behavior at program end / reset
At the end of the program or on reset, a specific default value can be assigned by the PLC
user program to every analog output in accordance with requirements, using the overwrite
mask, setting mask or disable signal.
Response to POWER ON
After POWER ON, the analog 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
overwrite or setting mask.
Analog NCK outputs without hardware
If analog NCK outputs, as defined via MD10310, 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 (DB10
DBB210 ...).
42
Function Manual, 03/2013, 6FC5397-1BP40-3BA1
Extended Functions