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© Siemens AG, 2006. All rights reserved
SINUMERIK 840D Configuring Manual NCU (PHD) – 03.06 Edition
System Overview
1.1 System configuration
A numeric control is modular in design. The central control units of an 840D
system are shown in Fig. 1-1:
Battery and fan slide-in module
Infeed/Regenerative feedback module Feed DriveMain Spindle DriveNCU box
Round cable to the
NCU terminal block
NCU
Device bus
I/R FDMSD
Fig. 1-1 Central control units SINUMERIK 840D
The subject of this document is the NCU, the central processing unit of the
840D controller. It contains the NC-CPU and the PLC-CPU.
The NCU has the following tasks:
Execute the NC program
Maintain communication with the peripherals.
Note
When using I/O devices, ensure that they are suitable for industrial use!
The NCU is installed in a housing called the NCU box. This housing also con-
tains a power supply and a fan subassembly.
Introduction
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