Example: Programming Without Spos; Special Case: Direction Of Rotation Reversal Via Nc/Plc Interface Signal In The Nc Program - Siemens SINUMERIK 840D Function Manual

Program code
N60 G331 Z-10 K5 S800
18.2.8.8

Example: Programming without SPOS

Program code
N05 M40 S500
...
N50 G331 S800
N60 G331 Z-10 K5
Thread interpolation for the spindle starts from the current position, which is determined by the
previously processed section of the part program, e.g. if the gear stage was changed.
Therefore, it might not be possible to remachine the thread.
Note
Please note that when machining with multiple spindles, the drill spindle also has to be the
master spindle. SETMS(<spindle number>) can be programmed to set the drill spindle as
the master spindle.
18.2.8.9

Special case: Direction of rotation reversal via NC/PLC interface signal in the NC program

Normally, a request to invert the direction of rotation of the spindle via the NC/PLC interface
signal "Invert M3 / M4" (DB31, ... DBX17.6) is realized by the PLC user program before the NC
program is started. Only when starting does the NC automatically evaluate the status of the
interface signal, and if necessary, change the spindle direction of rotation.
If, while the program is being executed, the spindle direction of rotation must again be changed
as a result of the NC/PLC interface signal "Invert M3 / M4" (DB31, ... DBX17.6), then within an
NC program, this can only be achieved using the subsequently described principle sequence:
N110 SPCOF or M5
N111 Mxx or Hxx
N112 STOPRE
Axes and spindles
Function Manual, 06/2019, A5E47437747B AA
Comment
; Tapping
; Gearbox stage cannot be changed,
; Monitoring the spindle speed, 800 rpm
; with gearbox stage data set 1: Gearbox stage 2
; should be active => Alarm 16748
Comment
; Programmed spindle speed: 500 rpm =>
; Gearbox stage 1 (20 to 1028 rpm)
; Master spindle: Gearbox stage 2 is selected
; Tapping
; Spindle acceleration from second gearbox stage data block 2
Stop the spindle and switch into the closed-loop speed controlled
mode
Output a user-specific help function to initiate the following ac‐
tions in the PLC user program:
● Set the read-in inhibit in the channel: DB21, ... DBX6.1 = 1
● Invert the interface signal "Invert M3/M4" of the spindle:
DB31, ... DBX17.6
● Reset the read-in inhibit in the channel: DB21, ... DBX6.1 = 0
Preprocessing stop
S1: Spindles
18.2 Operating modes
767