BECKHOFF BC2000 User Manual

LIGHTBUS
Bus Terminal Controller
BC2000

Technical Documentation

Version 1.1
2006-11-06

Please note the following

Target group

This description is only intended for the use of trained specialists in control
and automation engineering who are familiar with the applicable national
standards.

Safety requirements

The responsible staff must ensure that the application or use of the
products described satisfy all the requirements for safety, including all the
relevant laws, regulations, guidelines and standards.

The documentation has been prepared with care. The products described

are, however, constantly under development. For that reason the
documentation is not in every case checked for consistency with
performance data, standards or other characteristics, and does not
represent an assurance of characteristics in the sense of § 459, Para. 2 of
the German Civil Code. In the event that it contains technical or editorial
errors, we retain the right to make alterations at any time and without
warning. No claims for the modification of products that have already been
supplied may be made on the basis of the data, diagrams and descriptions
in this documentation.

©

This manual is copyrighted. Any reproduction or third party use of this
protected publication, whether in whole or in part, without the written
permission of Elektro Beckhoff GmbH, is forbidden.

Table of Contents

Table of Contents

1. Foreword 3

Notes on the documentation 3

Liability Conditions 3
Delivery conditions 3
Copyright 3

Safety Instructions 4

State at Delivery 4
Description of safety symbols 4

2. Basic Principles 5

Description of the BC2000 5
The Beckhoff Bus Terminal System 5
The interfaces 7

Electrical power supply 7
Power contacts feeding points 7
Power contacts 8
Fieldbus connection 8
Configuration and Programming Interface 8
Terminal Bus Contacts 8
Galvanic isolation 8

Operating Modes of the Bus Terminal Controller 9
Mechanical structure 10
Preparing for Operation and Diagnostics 12

3. The Beckhoff BC2000 Lightbus Coupler 15

Introduction to the Beckhoff Lightbus System 15

4. Settings in the TwinCAT System Manager 17

Basic Settings 17

PLC Cycle Time 18
PLC Variables 18
Remanent Variables 19
Terminal Bus Update 19
Program Download via the Fibre Optic Ring 19
Program Download via the RS232 Interface 20

ADS Functions 20

PLC Runtime System 21
Registers of the Bus Terminal Controller 22

Diagnostics in the BC2000 22

5. Settings in TwinCAT PLC 23

Terminal Bus Reset 23
Coupler Reset 23
Manufacturer’s Configuration 23
Cycle Time Measurement 23
Boot Project 23
Coupler Options 24

6. Appendix 25

Absolute Addressing in the BC2000 25

7. Index 26

8. Support and Service 27

Beckhoff's branch offices and representatives 27

Beckhoff Headquarters 27

BC2000 2

Foreword

Foreword

Notes on the documentation

This description is only intended for the use of trained specialists in control and automation engineering
who are familiar with the applicable national standards. It is essential that the following notes and
explanations are followed when installing and commissioning these components.

Liability Conditions

The responsible staff must ensure that the application or use of the products described satisfy all the
requirements for safety, including all the relevant laws, regulations, guidelines and standards.

The documentation has been prepared with care. The products described are, however, constantly under
development. For that reason the documentation is not in every case checked for consistency with
performance data, standards or other characteristics. None of the statements of this manual represents a
guarantee (Garantie) in the meaning of § 443 BGB of the German Civil Code or a statement about the
contractually expected fitness for a particular purpose in the meaning of § 434 par. 1 sentence 1 BGB. In
the event that it contains technical or editorial errors, we retain the right to make alterations at any time
and without warning. No claims for the modification of products that have already been supplied may be
made on the basis of the data, diagrams and descriptions in this documentation.

Delivery conditions

In addition, the general delivery conditions of the company Beckhoff Automation GmbH apply.

Copyright

©

This documentation is copyrighted. Any reproduction or third party use of this publication, whether in

whole or in part, without the written permission of Beckhoff Automation GmbH, is forbidden.

3 BC2000

Foreword

i

Safety Instructions

State at Delivery

All the components are supplied in particular hardware and software configurations appropriate for the
application. Modifications to hardware or software configurations other than those described in the
documentation are not permitted, and nullify the liability of Beckhoff Automation GmbH.

Description of safety symbols

The following safety symbols are used in this documentation. They are intended to alert the reader to the
associated safety instructions..

This symbol is intended to highlight risks for the life or health of personnel.

Danger

This symbol is intended to highlight risks for equipment, materials or the

Attention

environment.

This symbol indicates information that contributes to better understanding.

Note

BC2000 4

Basic Principles

Up to 64 bus terminals

each having 2 I/O channels
for each signal form

De-centralised wiring of
each I/O level

IPC as controller

Standard C - rail assembly

Modularity

Description of the BC2000

The BC2000 is a slave with PLC functionality. It has a fieldbus interface,
the Lightbus. The bus terminal controller is programmable, and is
programmed using the TwinCAT software in the IEC61131-3 programming
languages. Applied in combination with the C1220 or FC200x Lightbus PC
card and the TwinCAT PLC software, the BC2000 permits decentralisation
of the control tasks. This is a way of removing parts of the application out
of the central control system to relieve the CPU and the field bus.
Distributed counters, controllers and switches are typical applications for
the bus terminal controller. The reaction times are dependent upon the bus
communication and the overall control system, and maintenance of
function is possible even when the bus or control system fails (e.g. an
orderly transfer of the processes into a secure condition).

The Beckhoff Bus Terminal System

The bus terminal system is the universal interface between a fieldbus
system and the sensor / actuator level. A unit consists of a bus terminal
controller as the head station, and up to 64 electronic series terminals, the
last one being an end terminal. For each technical signal form, terminals
are available each having two I/O channels, and these can be mixed in any
order. All the terminal types have the same mechanical construction, so
that difficulties of planning and design are minimised. The height and depth
match the dimensions of compact terminal boxes.

Fieldbus technology allows more compact forms of controller to be used.
The I/O level does not have to be brought to the controller. The sensors
and actuators can be wired de-centrally, using minimum cable lengths. The
controller can be installed at any location within the plant. The use of an
industry PC as the controller means that the operating and observing
element can be implemented in the controller’s hardware. The controller
can therefore be located at an operating panel, in a control room, or at
some similar place. The bus terminals form the de-centralised input/output
level of the controller in the switching cabinet and the subsidiary terminal
boxes. The power sector of the plant is also controlled over the bus system
in addition to the sensor/actuator level. The bus terminal replaces the
conventional series terminal as the wiring level in the switching cabinet.
The switching cabinet can have smaller dimensions.

The Beckhoff bus terminal system unites the advantages of a bus system
with the possibilities of the compact series terminal. Bus terminals can be
driven within all the usual bus systems, thus reducing the controller parts
count. The bus terminals then behave like conventional connections for
that bus system. All the performance features of the particular bus system
are supported.

The easy, space-saving assembly on a standard C-rail, and the direct
wiring of actuators and sensors without cross-connections between the
terminals standardises the installation. The consistent labelling scheme
also contributes.

The small physical size and the great flexibility of the bus terminal system
allows it to be used wherever a series terminal is also used. Every type of
connection, such as analogue, digital, serial or the direct connection of
sensors can be implemented.

The modular assembly of the terminal strip with bus terminals of various

Basic Principles

5 BC2000

Basic Principles

End terminal

isolation

Potential

contacts

Supply voltage

II/O-Lightbus

Beckhoff Lightbus

Display of the channel state

K bus

End terminal

Potential feed terminals for
galvanically isolated groups

The principle of the
bus terminal

functions limits the number of unused channels to a maximum of one per
function. The presence of two channels in one terminal is the optimum
compromise of unused channels and the cost of each channel. The
possibility of galvanic isolation through potential feed terminals also helps
to keep the number of unused channels low.

The integrated LEDs show the state of the channel at a location close to
the sensors and actuators.

The terminal bus (known as the K bus) is the data path within a terminal
strip. The terminal bus is led through from the bus terminal controller
through all the terminals via six contacts on the terminals‘ side walls. The
end terminal terminates the terminal bus. The user does not have to learn
anything about the function of the terminal bus or about the internal
workings of the terminals and the bus terminal controller. Many software
tools that can be supplied make project planning, configuration and
operation easy.

The operating voltage is passed on to following terminals via three power
contacts. You can divide the terminal strip into arbitrary galvanically
isolated groups by means of potential feed terminals. The feed terminals
play no part in the control of the terminals, and can be inserted at any
points within the terminal strip.

Up to 64 terminals can be used within one terminal strip;
Potential feed terminals and end terminals are included in this count.

bus coupler
BC2000

for the
bus coupler

feed
terminal

Terminal bus

Additional characteristics of
the bus terminal controllers

0201

CYC

ERR

24V

0V

WD

PLC

+ +

BECKHOFF

BC2000

PE PE

Power

Galvanic

The bus terminal controller (BC) differs from the bus coupler (BK) in that in
addition to operating the terminal bus, a PLC task runs in the BC2000.
Unlike bus couplers, the signals from the terminals are processed by the
PLC task, while the fieldbus carries the in- and outputs of the PLC task.

It is also possible to partition the terminals in such a way that some of the
terminals are processed by the PLC task while others are passed over the
fieldbus to a master.

BC2000 6

02

01

+

+

PE

PE

B

C

K

H

O

24V

0V

00

X0

CYC

ERR

WD

II/O-Lightbus

Power LEDs

Bus coupler / power contacts

Terminal bus (K bus)

II/O-Lightbus

IN

OUT

Configuration

and programming

interface

Bus coupler power supply

24 V DC / GND

Power contacts

feeding points

Power contacts

WD

PLC

Bus terminal controllers for
various fieldbus systems

The Beckhoff BC2000
Lightbus coupler

Various bus terminal controllers can be used to couple the electronic
terminal strip quickly and easily to different fieldbus systems. It is also
possible to convert to another fieldbus system at a later time. The bus
terminal controller performs all the monitoring and control tasks that are
necessary for operation of the connected bus terminals. The operation and
configuration of the bus terminals is carried out exclusively by the bus
terminal controller. Nevertheless, the parameters that have been set are
stored in each bus terminal, and are retained in the event of voltage drop­out. Fieldbus, terminal bus and I/O level are galvanically isolated.

The interfaces

A bus terminal controller has six different methods of connection. These
interfaces are designed as plug connectors and as spring-loaded terminals.

Basic Principles

24 V DC to the topmost
terminals “24 V” and “0 V”

Bottom 3 terminal pairs for
feed

Maximum 24 V

Maximum 10 A

Electrical power supply

The bus terminal controllers require a 24 V DC supply for their operation.
The connection is made by means of the upper spring-loaded terminals
labelled “24 V” and “0 V”. The supply voltage feeds the bus terminal
controller electronics and, over the terminal bus, the bus terminals. The
power supply for the bus terminal controller electronics and that of the
terminal bus are electrically separated from the potential of the field level.

Power contacts feeding points

The bottom six connections with spring-loaded terminals can be used to
feed the supply for the peripherals. The spring-loaded terminals are joined
in pairs to a power contact. The feed for the power contacts has no
connection to the voltage supply for the bus terminal controller. The design
of the feed permits voltages of up to 24 V. The assignment in pairs and the
electrical connection between feed terminal contacts allows the connection
wires to be looped through to various terminal points. The current drawn
from the power contacts must not exceed 10 A for long periods. The
current rating between two spring-loaded terminals is identical to that of the
connecting wires.

7 BC2000

Basic Principles

Spring contacts on the side

Beckhoff Lightbus
Fibre optic ring

Beckhoff Z1000 connector

Serial interface under the
front cover

6 contacts on the side

3 potential groups:
Field bus
Terminal bus (K bus)
Peripheral level

Power contacts

On the right hand face of the bus terminal controller there are three spring
contacts for the power contact connections. The spring contacts are hidden
in slots so that they can not be accidentally touched. By attaching a bus
terminal the blade contacts on the left hand side of the bus terminal are
connected to the spring contacts. The tongue and groove guides on the top
and bottom of the bus terminal controllers and of the bus terminals
guarantees that the power contacts mate securely.

Fieldbus connection

There is a recessed front face on the left hand side. The typical Beckhoff
Lightbus connector can be inserted here. The Beckhoff Lightbus consists
of an optical fibre ring into which the bus terminal controller is inserted.
Here the plug out of which red light shines when the Beckhoff Lightbus is
switched on is inserted into the upper socket. On the figure this is labelled
with „IN“. Optical fibre connectors of type Beckhoff Z1000 are required for
the connection.

Configuration and Programming Interface

The bus terminal controllers have an RS232 interface at the bottom of the
front face. The miniature connector can be joined to a PC with the aid of a
connecting cable and the KS2000 configuration software. The interface
permits the bus terminals to be configured, for example adjusting the
amplification factors of the analogue channels. The interface can also be
used to change the assignments of the bus terminal data to the process
image in the bus terminal controller. The functionality of the configuration
interface can also be reached via the fieldbus using string communication
facility.
This interface is also used for programming the BC2000. The cable for the
interface is supplied along with TwinCAT BC.

Terminal Bus Contacts

In order to connect the bus terminal controller to the bus terminals, the bus
terminal controller has gold contacts on the right hand side. When the bus
terminals are pushed together the gold contacts automatically make the
connection between the bus terminals. The voltage supply to the terminal
bus electronics in the bus terminals and the data exchange between the
bus terminal controller and the bus terminals is carried out by the terminal
bus. A part of the data exchange takes place via a ring structure within the
terminal bus. Opening the terminal bus, e.g. by pulling out one of the bus
terminals, opens the ring. Data exchange is no longer possible. Special
mechanisms nevertheless allow the bus terminal controller to identify the
location of the interruption and to report it.

Galvanic isolation

The bus terminal controllers operate by means of three independent
potential groups. The supply voltage feeds the terminal bus electronics in
the bus terminal controller and the terminal bus itself, which is electrically
separate. The supply voltage is also used to generate the operating
voltage for the fieldbus.

Remark: All the bus terminals are galvanically isolated from the terminal
bus. The terminal bus is thus galvanically isolated from everything else.

BC2000 8