Indirect I/O Access Via Plc; Brief Description - 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

Monitoring
The following monitoring functions are active for the NC I/Os:
● Ramp-up:
– Check for consistency of the I/Os detected on the PLC and the NC I/O parameterized
● Cyclic operation:
– Sign-of-life monitoring in interpolation cycles
– Module monitoring in interpolation cycles
– Temperature monitoring
In the event of an error, the DB10.DBX104.7 "NC ready" signal is reset and an alarm is
displayed.
Response to faults
The digital and analog outputs of the NC I/O are switched to a safe status (0 V) in the event
of faults (e.g. NC ready = 0), for errors in the NCU or power failures.
Application
The NC I/O is used, for example, by the following NC functions:
● Several feedrate values or auxiliary functions in one block
● Rapid retraction on final dimension
● Axis-specific delete distance-to-go
● Program branches
● Rapid NC Start
● Analog calipers
● Position switching signals
● Punching/nibbling functions
● Analog-value control
2.2 Indirect I/O access via PLC
2.2.1

Brief description

There are three I/O interfaces (X122, X132 and X142) on the SINUMERIK 840D sl NCU.
Four digital inputs and outputs of the X142 interface are available as so-called fast NC I/O.
They can be read or written via the first address byte and via the $A_IN[1...4] and $A_OUT[1...4]
system variables.
30
in the machine data.
Function Manual, 10/2015, 6FC5397-1BP40-5BA3
Extended Functions