Supplementary Conditions For Link Axes - Siemens SINUMERIK 840D sl Function Manual

Several Operator Panels on Several NCUs, Distributed Systems (B3)
Link axes
Examples
An NC program with M3 S1000 is executed for the 7th channel on NCU_2. This spindle
corresponds to the 5th machine axis of NCU_1 and is therefore link axis. Therefore the
auxiliary function output here for NCU_2 is in Channel 7 with the axis number 0, as the link
axis is on another NCU (NCU_1 here). On the PLC of NCU_2, this results in the output of:
DB21, ... DBW68 (extended address of the M function (16-bit INT))
DB21, ... DBD70 (M function 1 (INT 3))
DB21, ... DBW98 (extended address of S function 1)
DB21, ... DBD100 (S function 1 (REAL 100))
In parallel, the information of the system auxiliary functions is transferred from NCU_2 via the
NCU link to NCU_1 (home NCU of the link axis). The system auxiliary functions M3 S1000
for the 5th machine axis are output from here.
The PLC on NCU_1 then supplies the following axial signals on the PLC user interface for
machine axis 5:
DB35, ... DBW86 (M function (INT 3) for spindle)
DB35, ... DBD88 (S function (REAL 100) for spindle).
2.6.4

Supplementary conditions for link axes

Output of alarms from position controller or drive
Axis alarms are always output on the NCU which is producing the interpolation value. If an
alarm is generated for a link axis by the position controller, then the alarm is transferred to
the NCU which is currently processing the interpolation.
On the assumption that axis alarms which cause the NCK-Ready relay to drop out (Nck-
NoReady) are attributable to faults on the drive bus, the alarm is also output on the NCU on
which the axis or the drive bus is physically operated. The reaction "Ready relay dropout" is
only activated on this NCU.
Output of alarms following EMERGENCY STOP
If an EMERGENCY OFF request is activated by the PLC on an NCU, all axes physically
connected to drives on this NCU are switched to follow-up mode. This means that: even
axes which are being interpolated by a different NCU are also switched to follow-up. Since
this status prevents any further constructive machining operations on the other NCUs, an
additional alarm is generated which is designed to stop all axis motion instantaneously.
This additional alarm must be acknowledged by an NC reset. If the original alarm is still
active at this time, then the additional alarm can be successfully reset, but another alarm
(self-clearing) is then produced which prevents axis motion or a new program start until the
original alarm has been reset.
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Function Manual, 03/2009, 6FC5397-1BP10-4BA0
Extended Functions