Digital Outputs - Siemens SINUMERIK 840D sl Function Manual

A4: Digital and analog NC I/O for SINUMERIK 840D sl
2.2 Indirect I/O access via PLC
The actual value reflects the actual state of the signal at the hardware input. The influence of
the PLC is ignored for the "actual value".
Disable input
Digital NC inputs can be disabled individually from the PLC user program:
DB10 DBB0 or DBB122 ... (disable of the digital NC inputs)
In this case, they are set to a defined "0" inside the control.
Set input from PLC
The PLC can also set each digital input to a defined "1" signal:
DB10 DBB1 or DBB123 ... (setting of the digital NC inputs from the PLC)
As soon as this interface signal is set to "1", the signal state at the hardware input or the input
disable is inactive.
Behavior during POWER ON / reset
After POWER ON and reset, the signal level at the respective input is passed on. If necessary,
the PLC user program can disable or set the individual inputs to a defined "1" as described
above.
2.2.5.2

Digital outputs

Function
Time-critical switching operations can be triggered very quickly via the digital NC outputs,
bypassing the PLC cycle times for the relevant machining and program-controlled (e.g. with
the block change).
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.
Applications
Digital NC outputs are used, for example, for the following NC functions:
● Position switching signals (see Section "N3: Software cams, position switching cycles - only
840D sl (Page 589)")
● Output of comparator signals
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Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Extended Functions