Siemens SINUMERIK 840D sl Function Manual page 43

Disable input
Analog NC inputs can be disabled individually from the PLC user program:
DB10 DBB146 (disable of the analog NC inputs)
In this case, they are set to a defined "0" inside the control.
Set input from PLC
The PLC can also specify a value for each analog NC input:
DB10 DBB147 (analog value specification for NC from the PLC)
As soon as this interface signal is set to "1", the setting value set by the PLC becomes active
for the corresponding analog input.
DB10 DBW148-162 (setpoint from the PLC for the analog NC input)
The analog value at the hardware input or the input disable is then inactive.
Weighting factor
The weighting factor can be used to adapt each individual NC input to the various AD
converters (depending on the I/O module ) for reading in the part program:
MD10320 $MN_FASTIO_ANA_INPUT_WEIGHT[<n>]
In this machine data, it is necessary to enter the value x that is to be read in the part program
with the system variable $A_INA[<n>], if the corresponding analog input <n> is set to the
maximum value or if the value 32767 is set for this input via the PLC interface. The voltage
level at the analog input is then read with system variable $A_INA[<n>] as a numerical value
with the unit millivolts.
Note
Application for analog NC inputs 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 input 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 during POWER ON / reset
After POWER ON and reset, the analog value at the respective input is passed on. If necessary,
the PLC user program can disable or set the individual inputs to a setpoint.
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
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