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Sinumerik 840D (PowerLine)
1 Configuration
1.1 Overview
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drawing
part
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The CNC (computer numerical control) term refers to these machines
that utilize computer logic to control movements and perform the
metalworking.
The front of the controller has a video screen
that displays the program information, position, speeds and feeds, and
other data required for the operator to monitor the machine's
performance. Also on the front panel are the data entry keys, data
connection ports, and start-stop switches. On SINUMERIK controllers,
this interface is called Man Machine Communication (MMC) or Human
Machine Interface (HMI).
The NC is always reading machine
position from position encoders (linear scales, rotary encoders, etc.)
and control the axis motor speed so the programmed position to be
reached and / or maintained.
The PLC (Programmable Logic
Controller) read various input signals from the machine (such as
information from buttons, keys, actuators) and reacts according to a
programmed logic sending output signals to the machine (controlling
pumps, vents, brakes or light signals).
All CNC machine tools present a high degree
of automation, reducing
or eliminating the operator intervention. This helps achieving high
accuracy and repeatability in machining large numbers of identical
parts / work-pieces. On the other hand, changing the production from
one type of work-piece to another can be as easy as loading a different
program.
1.2 840D structure
In the standard structure of
the 840D, a PCU unit is used for Man-Machine communication tasks. PCU
is mounted on the back of an OP unit, the OP providing keyboard and
screen for PCU unit.
The NC / PLC are included into NCK board,
integrated into the drives architecture and connected to drives through
a high speed digital bus.
Communication between NC /PLC board
and PCU board is done via an MPI (Multi Point Interface) connection
also called OPI (Operator Panel Interface).
Since MPI is a standard interface for Siemens PLC’s, some PLC periphery may share the
same cable / connection. MCP (Machine Control Panel), HHU (Hand Held
Unit) are just some examples of the PLC I/O units usually connected to
OPI. Still, these units are PLC periphery and there is no direct
communication between these units and NC control.
The NCK
module (including the NC kernel and the PLC CPU) is integrated into the
611D drive rack, right between IR module and the first drive. A digital
bus connects the NC to all drive control units.
All the position
encoders are connected to drives units and the information is then
transmitted to NC unit through the digital bus.
An OPI link
(Operator Panel Interface - in fact an MPI link with 1.2MB speed) is
connecting the NC to PCU unit, mounted on the back of the OP.
Since
this OPI link is in fact similar to an MPI connection, the MCP (Machine
Control Panel) can also share the same bus in order to connect as PLC
periphery. Note that there is no direct communication between NC and
MCP.
The Step7 periphery can be connected either using IM361
modules (multi tier configuration of the Step7) either through PROFIBUS
connection.
Ref.: Catalog NC60
1.3
NC internal structure
There are various types of NCK boards:
NC571.x - max 6 axes
NC572.x - mid range
NC573.x - high range
First, the NCK board is inserted into the NCU Box. The battery and NC
fan are also connected to NCU Box (so if NCK board is removed from NCU
Box it is also detached from the backup battery).
A PCMCIA card containing NC system software (NC operating system and
software) and also some software options is inserted into the NCK unit.
A small overview of the data structure is showed in the picture.
Please note that the 611D SW is also stored on the PCMCIA card and is
loaded into the drives unit at every NCK power on. All the drives
parameters (such as motor data, encoder data, etc.) are stored as a
boot file into the NCK Static RAM and also loaded at every NCK power
on. During Power Off state no data is stored in 611D units.
Ref.: Catalog NC60
1.4 NC external view
NCK board supply voltage is coming from 611 power
supply through the Device Bus interface. NCK does not use this
interface for communication.
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Reset (S1)
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Button
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Triggering hardware reset to reset the control and drive followed by a complete restart.
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| NMI (S2) |
Button |
Triggering an NMI request at the processor |
| S3 |
Rotary switch |
NCK start-up switch |
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Position 0: normal mode |
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Position 1: start-up position |
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Positions 2 to 7: reserved
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S4
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Selector
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PLC-mode switch
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Position 0: PLC–RUN
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Position
1: PLC–RUN–P
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Position
2: PLC–STOP
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Position 3: MRES
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H1
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LED
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+5V/POK: ... supply voltage is in tolerance range.
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Green
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Left
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Illuminates if...
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NF:
... NCK-Watchdog has activated and during start-up.
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Red
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...
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CF:
...COM- Watchdog has activated.
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Red
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CB:
... data transfer takes places via
OPI (BTSS).
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Yellow
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CP:
... data transfer takes
place via PG
MPI interface.
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Yellow
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H2
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LED
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PR:
... if PLC-status = RUN
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Green
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Right
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Iluminates if...
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PS: ... if PLC-status = STOP
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Red
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PF: ... + PR + PS + PFO: if PLC-Watchdog has activated.
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Red
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PFO: ... if PLC-status = FORCE |
Yellow
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T/DP: ... PLC-DP-status
(on some PLC-CPU's is called "BUSF")
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Yellow
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H3
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7 segment
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Situation
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. (decimal point) |
An error was identified in the cyclical operation.
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| 0 |
Real mode may have been switched to Protected mode. |
| 1 |
Start of download from the PCMCIA card. |
| Number with decimal point |
The number of the module that has just been downloaded appears on the status display. |
| 2 |
Download from the PCMCIA card has ended succesfully. |
| 3 |
The debug mnitoring is initialized. |
| 4 |
Operating system was downloaded succesfully. |
| 5 |
Operating system has started up. |
| 6 |
NCK software is initialized. |
Ref: “Configuring the NCU” [PHD.PDF], 03/2006 edition, chap. 4:
“Description of the NCU”
“Start-Up Guide 840D/810D/611D” [IADC.PDF] 03/2006 edition, chap. 5
“Power-On and Power-Up”
1.5 MPI configuration
Example of
MPI configuration
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