Control

With CNC-machining centres a certain speciality with machine control follows.

On the contrary to most machine controls, this is not a single unit, which is located in the carcass.

Most modern CNC-machining centres are equipped with a customary PC. All programs are saved on this one, for the operator only this PC is accessible.

But a normal PC-operating system doesn't process data in realtime. It's not suitable to head for a machine, where single axis movements are combined with a resulting rail, as comparisons of targeted and actual values and possibly corrections within milli-seconds have to take place.

The programming of realtime-control directly in the machine code isn't considered up-to-date for a longer period.

Hence the programming on a PC takes place in a for most operators, familiar programming surface.

The data eventually go as set-wise code to a SPS, also often called as the actual "control" of CNC.

The SPS can process the signals in realtime and forwards them as control signals to the single axis cards, which in turn head to the servor motors of the axis directly.

Variations:

  • PC with realtime-business system: the manufacturer Biesse uses the realtime-operating system Windows Real Time with some machines, so that the SPS can be places in the PC as a card and is omitted as single component.

  • Integrated control: today scarcely used, but especially widely-used variation in the 90's where industry PC and SPS were located in a common carcass, partially with an own operating system.

Images

Für den Bediener sichtbarer Teil der Steuerung mit Touchscreen
HOMAG, 2016
Steuerung mit handelsüblichem Standard-PC
BIESSE, 2000
SPS-Steuerung NUM 1020 im Schaltschrank einer Morbidelli Author 500
NUM, 2002
ESA Kvara PLC control in the control cabinet of an SCM Cyflex F900
SCM, 2009