Siemens SINUMERIK 840D sl Function Manual page 47

Weighting factor
The weighting factor can be used to adapt each individual NC 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 NC output 1
$A_OUTA[3] = -4120; -4.12 V is output at analog NC output 3
Note
Application for analog NC 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 analog I/O values (Page 48)".
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 NC outputs without hardware
If analog NC outputs, as defined via MD10310, are written by the part program, but are not
available as hardware, no alarm is output. The NC value can be read by the PLC (DB10
DBB210 ...).
Extended Functions
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
A4: Digital and analog NC I/O for SINUMERIK 840D sl
2.2 Indirect I/O access via PLC
47