Starting Command Axes - Siemens SINUMERIK 840Di sl Function Manual

Note
Axis motion disable can also be programmed for PLC axes (e.g. magazine axis).
2.4.13

Starting command axes

Introduction
Axes can be positioned, started and stopped completely asynchronously to the part program
from synchronized actions. This type of programming is advisable for cyclic sequences or
sequences that are strongly dependent on events. Axes started from synchronized actions
are called command axes.
Control from the PLC
Autonomous singleaxis operations
A command axis interpolated from the main run (started by static synchronized actions)
reacts independently of the NC program in the event of NC Stop, alarm handling, end of
program, program control and RESET, when control of the command axis has been taken
over from the PLC.
The control of the command axis is done via the axial VDI interface (PLC→NCK) by means of
the NST:
DB 31, ... DBX28.7 == 1 (PLC controls axis/P5)
For more information about the precise sequence of operations of the various steps for
transferring control of the command axis to the PLC, please see:
References:
/FB2/ Function Manual, Extended Functions; Positioning Axes (P2)
Boundary condition
An axis cannot be moved from the part program and from synchronized actions
simultaneously. but may be moved from these two sources successively.
Delays may occur if an axis has been moved first from a synchronized action and then
programmed again in the part program.
Note
MD 30450 $MA_IS_CONCURRENT_POS_AX indicates whether the axis is primarily
intended as a command axis or for programming by the part program:
0: no competing axis
1: competing axis (command axis)
Synchronized actions
Function Manual, 11/2006, 6FC5397-5BP10-2BA0
Detailed description
2.4 Actions in synchronized actions
69