Burkert buS User manual

Type büS
Bürkert System Bus
Design Guideline

We reserve the right to make technical changes without notice.
© 2020 - 2022
Operating Instructions 2207/01_EU-EN 00815392 / Original EN

Type büS
Contents
3
CONTENTS
1 Symbols used .............................................................................................................................................6
2 Introduction ................................................................................................................................................7
2.1 Preface ............................................................................................................................................. 7
2.2 What is the Bürkert system bus (büS/EDIP)? ................................................................................... 7
2.3 For whom is this Design Guideline intended? .................................................................................. 7
2.4 What is the purpose of the Design Guideline? ................................................................................. 7
2.5 Bürkert quality standard ................................................................................................................... 7
3 Creating a rough project plan ....................................................................................................................8
3.1 Block diagram, devices, postion, protocols ..................................................................................... 8
4 Getting to know the basics of a büS infrastructure – accessories, cables, pin assignment ..................9
4.1 What is the purpose of the various accessories............................................................................... 9
4.2 Accessories ...................................................................................................................................... 9
4.2.1 Y-connector .........................................................................................................................9
4.2.2 Passive junction box ..........................................................................................................10
4.2.3 Gender changer .................................................................................................................10
4.2.4 Termination ........................................................................................................................11
4.3 Cable configuration ........................................................................................................................ 11
4.3.1 Characteristic impedance and cables standards ..............................................................11
4.3.2 Connecting cables .............................................................................................................11
4.3.3 Extension cables................................................................................................................11
4.4 Pin assignment ............................................................................................................................... 12
4.4.1 M12 connector male, 5-pin (A-coded)...............................................................................12
4.4.2 M12 connector male, 8-pin (A-coded)...............................................................................12
4.4.3 Terminal block, 5-pin .........................................................................................................12
4.4.4 Terminal block, 4-pin .........................................................................................................13
5 Getting to know the büS topologies........................................................................................................14
5.1 What is a bus topology and why do you need it? .......................................................................... 14
5.2 Common terms of bus topology..................................................................................................... 14
5.2.1 Trunk line ...........................................................................................................................14
5.2.2 Stub line .............................................................................................................................14
5.2.3 Overview of cable lengths..................................................................................................14
5.2.4 Example .............................................................................................................................14
5.3 Which topologies are recommended? ........................................................................................... 15
5.3.1 Line topology (daisy chain) ................................................................................................15
5.3.2 Line topology with stub lines .............................................................................................15
5.3.3 Star topology .....................................................................................................................16
5.4 Which topologies are NOT recommended? ................................................................................... 16
5.4.1 Tree topology.....................................................................................................................16
5.5 Which topologies are NOT permitted ............................................................................................. 17
5.5.1 Ring topology.....................................................................................................................17
6 Detailed project plan 1 .............................................................................................................................18
6.1 Floor plan........................................................................................................................................ 18
6.1.1 Network with a junction box ..............................................................................................18

Type büS
Contents
4
6.1.2 Network with Y-connectors ...............................................................................................18
6.1.3 Mixed network ...................................................................................................................19
7 Technical know-how ................................................................................................................................20
7.1 Termination resistors ...................................................................................................................... 20
7.2 Connection for diagnostics ............................................................................................................ 20
8 Detailed project plan 2 .............................................................................................................................21
8.1 Completion – floor plan .................................................................................................................. 21
8.1.1 Network with a junction box ..............................................................................................21
8.1.2 Network with Y-connectors ...............................................................................................21
8.1.3 Mixed network ...................................................................................................................22
9 Network power supply .............................................................................................................................23
9.1 Power segments............................................................................................................................. 23
9.1.1 One power segment ..........................................................................................................23
9.1.2 Additional power supply ....................................................................................................23
9.2 Rule of thumb ................................................................................................................................. 23
10 Detailed project plan 3 .............................................................................................................................24
10.1 Cabling plan.................................................................................................................................... 24
10.1.1 Network with junction box .................................................................................................24
10.1.2 Network with Y-connectors ...............................................................................................24
10.1.3 Mixed network ...................................................................................................................25
11 büS network shielding..............................................................................................................................26
11.1 Shielding of EDIP devices .............................................................................................................. 26
11.2 Comparison of shieldings............................................................................................................... 26
11.3 Network with direct shielded devices............................................................................................. 27
11.4 Network with RC shielded devices................................................................................................. 28
11.5 Network with none shield connected devices................................................................................ 29
11.6 Mixed network with various shieldings........................................................................................... 30
12 Best practice instructions ........................................................................................................................32
12.1 Termination resistor........................................................................................................................ 32
12.2 Signal reflections ............................................................................................................................ 32
12.3 Passive junction box....................................................................................................................... 32
12.4 Diagnostic port ............................................................................................................................... 32
12.5 Baud rate ........................................................................................................................................ 32
12.6 büS stick......................................................................................................................................... 32
12.7 Stub lines........................................................................................................................................ 32
12.8 Bus load.......................................................................................................................................... 32
12.9 Power consumption........................................................................................................................ 33
12.10 Grounding power supplies ............................................................................................................. 33
12.11 Shielding of büS network ............................................................................................................... 33
13 büS networks with maximum network expansion ..................................................................................34
13.1 Line topology .................................................................................................................................. 34

Type büS
Contents
5
13.1.1 500 kbit/s ...........................................................................................................................34
13.1.2 250 kbit/s ...........................................................................................................................35
13.1.3 125 kbit/s ...........................................................................................................................36
13.2 Star topology with a junction box................................................................................................... 37
13.3 Tree topology with a junction box .................................................................................................. 37
14 Troubleshooting .......................................................................................................................................38
14.1 Sporadic disconnections................................................................................................................ 38
14.2 Red LED (failure) ............................................................................................................................. 38
14.3 Orange LED on the device (functional check) ................................................................................ 38
14.4 Yellow LED on the device (out of specification) ............................................................................. 39
14.5 Blue LED on the device (maintenance required) ............................................................................ 39
14.6 Restarting some devices ................................................................................................................ 40
15 Appendix...................................................................................................................................................41
15.1 Accessories - büS stick interface sets ........................................................................................... 41
15.2 Accessories - connectors............................................................................................................... 41
15.3 Accessories - cables (open leads).................................................................................................. 41
15.4 Accessories - extension cables...................................................................................................... 42
15.5 Accessories - power supplies ........................................................................................................ 42
15.6 Accessories - power cables ........................................................................................................... 42

Type büS
Symbols used
6
1 SYMBOLS USED
Diagnostics
Termination resistor
TR
PS Power supply
Measurement point
MP
Trunk line
Stub line
YY-connector with interrupt
YY-connector

Type büS
Introduction
7
2 INTRODUCTION
2.1 Preface
The aim of this Design Guideline is to provide you with practical information on how to plan your automation
plant using Bürkert devices based on the Bürkert system bus (büS). The various aspects involved in the
planning, assembly and operation processes are all considered. The structure of the Design Guideline helps
you build knowledge and apply it through different steps based on examples.
2.2 What is the Bürkert system bus (büS/EDIP)?
The Bürkert system bus, also referred to as büS, is based on the widely spread CANopen standard and is
fully downwards compatible to this standard. The büS concept does not require a master. Field devices can
easily interchange process data and detailed diagnostic data. A gateway allows access to this information
from a higher-level system. The Bürkert digital device platform EDIP (Efficient Device Integration Platform)
opens the door to endless possibilities for a digital future.
2.3 For whom is this Design Guideline intended?
The Design Guideline is intended for engineers or plant builders who are familiar with the planning and en-
gineering of automation plants containing fieldbuses, especially CAN-based protocols like CANopen and
DeviceNet. The Design Guideline summarises the additional knowledge required to plan büS/EDIP net-
works. The most important steps for planning, creating and commissioning büS devices are outlined herein.
2.4 What is the purpose of the Design Guideline?
The Design Guideline aids the planning of a büS/EDIP system. In a comprehensive approach based on illus-
trative and practical examples, the Design Guideline walks you through the Do’s & Don’ts to ensure a fully
functional system.
This Design Guideline explains in detailed individual steps how to plan a büS network.
2.5 Bürkert quality standard
All devices with a büS/EDIP interface have to obtain an internal certification which consists of a software
and hardware measurement. Therefore, we can ensure that all Bürkert devices have attained the same
quality standard. Currently, there are two approved CAN transceivers that meet these requirements.

Type büS
Creating a rough project plan
8
3 CREATING A ROUGH PROJECT PLAN
3.1 Block diagram, devices, postion, protocols
Which devices are planned?
Create an overview of the positioning of your devices.
Are the devices distributed in an equidistant or a non-equidistant manner?
Device 1
Device 2
Device 3
Device 4
Device 5
Device n
equidistant non-equidistant
PROFINET
büS
Fig.1: Project plan

Type büS
Getting to know the basics of a büS
infrastructure – accessories, cables,
pin assignment
9
4
4.1
GETTING TO KNOW THE BASICS OF A büS
INFRASTRUCTURE – ACCESSORIES, CABLES,
PIN ASSIGNMENT
What is the purpose of the various accessories
In this chapter, the various components required for cabling are explained in detail.
büS devices are widely equipped with standard M12 connectors and. different accessories are available for
a range of cabling tasks.
4.2 Accessories
4.2.1 Y-connector
Definition: A Y-connector has three M12 connectors in total. On one side of the connector, there is one
male and one female connector. On the other side, there is one female connector.
Purpose: Since most büS devices have a single M12 büS connector, the Y-connector enables another con-
nection option to the next device. The single connector side is connected to the device and the other two
connectors may be used for the devices to the left and the right.
Bürkert
order no.
36
45
Bürkert Id.Nr.
772420
12
1
2
3
4
5
1
2
3
4
5
12345
M12 female
M12 female M12 male
Fig.2: Y-connector
A Y-connector with interrupt is also available. This connector is used for segmenting power. The pin 2 con-
nection is interrupted. It is therefore possible to use a new power supply for the next büS segment if the
limit of 100W has been reached.
1
2
3
4
5
1
2
3
4
5
12345
M12 female
M12 female M12 male
Bürkert
order no.
36
45
Bürkert Id.Nr.
772420
12
Fig.3: Y-Connector with interrupt

Type büS
Getting to know the basics of a büS
infrastructure – accessories, cables,
pin assignment
10
4.2.2 Passive junction box
Definition: A passive junction box is an IP65/IP67 block with connectors for the power supply and multiple
büS connectors. It is a passive module and, therefore, does not have to be configured.
Purpose: The passive junction box allows multiple connections to büS devices in a star form. The Y-con-
nectors on each device become redundant when using a passive junction box, thus making cabling in the
field much simpler.
Fig.4: Passive junction box
4.2.3 Gender changer
Definition: A gender changer is an IP65/67 component with two male M12 connectors.
Purpose: It is used to connect two female M12 connectors.
Bürkert
772867
Fig.5: Gender changer

Type büS
Getting to know the basics of a büS
infrastructure – accessories, cables,
pin assignment
11
4.2.4 Termination
Definition: A termination resistor is available as an M12 connector (female and male) or as a chip and has to
be used twice in one network.
Purpose: To avoid signal reflections in the cable, the büS network always needs to be terminated with two
120Ω resistors at the ends of the cable. One is required at the beginning of the network and one at the end.
Bürkert Id Nr
772424
Fig.6: Termination
Fig.7: Termination resistor chip
4.3 Cable configuration
There are two types of cable: connecting cables and extension cables. All cables are available with different
cable lengths. An overview can be found in the appendix.
4.3.1 Characteristic impedance and cables standards
All nodes are connected to each other through a physically conventional two-wire bus. The wires are a twis-
ted pair with a 120 Ω (nominal) characteristic impedance. CiA 301 (CANopen application layer) is standard-
ised as EN 50325-4.
4.3.2 Connecting cables
Definition: Connecting cables are equipped with a female M12 connector on one side and with open leads
on the other.
Purpose: These cables connect a device with a terminal block to an M12 connector, e.g. gateway Type
ME43.
4.3.3 Extension cables
Definition: Extension cables are equipped with a female M12 connector on one side and with a male M12
connector on the other.
Purpose: These cables are used to connect a device with an M12 connector.

Type büS
Getting to know the basics of a büS
infrastructure – accessories, cables,
pin assignment
12
4.4 Pin assignment
Various standard connectors are available for Bürkert devices with a büS interface.
4.4.1 M12 connector male, 5-pin (A-coded)
M12 connector male, 5-pin (A-coded) Pin Assignment
1
2
3
4
5
1 SHIELD
2 V+
3 DGND
4 CAN_H
5 CAN_L
Tab.1: M12 connector male, 5-pin (A-coded)
4.4.2 M12 connector male, 8-pin (A-coded)
M12 connector male, 8-pin (A-coded) Pin Assignment
1
2
4
6
7
3
5
8
1 V+
2 DGND
3 CAN_L
4 CAN_H
5 Device specific
6 Device specific
7 Device specific
8 Device specific
Tab.2: M12 connector male, 8-pin (A-coded)
4.4.3 Terminal block, 5-pin
Terminal block, 5-pin Pin (colour) Assignment
24V
H
Shield
L
GND
Red 24 V DC
White CAN_H (büS-connection)
Green SHIELD
Blue CAN_L (büS-connection)
Black GND
Tab.3: Terminal block, 5-pin

Type büS
Getting to know the basics of a büS
infrastructure – accessories, cables,
pin assignment
13
4.4.4 Terminal block, 4-pin
Terminal block, 4-pin Pin Assignment
123 4
1 DGND
2 CAN_L
3 CAN_H
4 +24 V DC
Tab.4: Terminal block, 4-pin

Type büS
Getting to know the büS topologies
14
5 GETTING TO KNOW THE BÜS TOPOLOGIES
5.1 What is a bus topology and why do you need it?
The arrangement of different devices on the bus defines the topology. Different topologies influence the
quality of communication and certain topologies are, therefore, recommended to achieve a good network
design.
5.2 Common terms of bus topology
5.2.1 Trunk line
A trunk line is the main part of a CANopen cabling solution. All devices and junction boxes are connected to
it.
5.2.2 Stub line
A stub line is a branch of the trunk line and allows connection to a device that is not located close to the
trunk line. The use of stub lines must be avoided as much as possible. However, there are several limita-
tions depending on the baud rate of the network.
5.2.3 Overview of cable lengths
Overview of maximum cable lengths in the CANopen specification:
Baud rate max. trunk length max. stub line length max. length all stubs
50 kbit/s 1000 m 50 m 250 m
125 kbit/s 500 m 20 m 100 m
250 kbit/s 250 m 10 m 50 m
500 kbit/s 100 m 5 m 25 m
1 Mbit/s 20 m 1 m 5 m
Tab.5: Cable lengths
This table shows an overview of theoretical values for an ideal network. Nevertheless, there are more de-
pendencies regarding the trunk line length, the stub line length, the amount of process data and the baud
rate.
5.2.4 Example
Trunk
Stub
Device 3
Device 2
Device 4
Device 5
Device 6
Device n
Junction box
Device 1
Fig.8: Example

Type büS
Getting to know the büS topologies
15
5.3 Which topologies are recommended?
The following topologies achieve the best results with regard to signal quality.
5.3.1 Line topology (daisy chain)
All devices are connected in single row without a stub line.
Device 1 Trunk
Device 2 Device n
Fig.9: Line topology
5.3.2 Line topology with stub lines
The trunk line of the network is connected directly to the next device. If this is not possible, use a stub line.
Avoid stub lines as much as possible and keep them short. Please note the maximum stub line length that
depends on the baud rate.
Device 2 Trunk
Stub
Device 4
Device 1 Device 3 Device n
Fig.10: Line topology with stub lines

Type büS
Getting to know the büS topologies
16
5.3.3 Star topology
A star topology is used to interconnect devices when space is limited and a setup with a daisy chain topo-
logy is not possible.
Stub
Junction box
Device 3
Device 1 Device n
Device 2
Fig.11: Star topology
5.4 Which topologies are NOT recommended?
The topologies in this chapter are possible, but various criteria have to be observed to ensure the network
works properly.
5.4.1 Tree topology
For signal quality, it is not recommended to use a tree topology. Cascading of the passive junction boxes is
restricted to three. If more devices are needed, it is necessary to interconnect the trunk lines of the passive
junction boxes and to not cascade more than three devices. Otherwise, the maximum stub line length is ex-
ceeded and errors may occur.
Stub
Junction box 1
Device 3
Device 1
Device n
Device 2
Junction box 2 Junction box n
Fig.12: Tree topology

Type büS
Getting to know the büS topologies
17
5.5 Which topologies are NOT permitted
The topologies described in this section are not permitted. Never use them in a büS or CANopen network.
5.5.1 Ring topology
A ring topology is not permitted in a CANopen network. Choose another topology for the network.
Trunk
Device 2 Device n
Device 1
Device 3
Fig.13: Ring topology

Type büS
Detailed project plan 1
18
6 DETAILED PROJECT PLAN 1
6.1 Floor plan
Create a detailed project plan using the aforesaid information about devices, cables lengths, topology, junc-
tion boxes and Y-connectors.
Are the devices close to each other?
YES: plan the network with a passive junction box
NO: plan the network with Y-connectors
Rules:
▪Connect all the accessories on the trunk line
▪Connect the accessories directly to the device
– Use stub lines to connect the devices
– Avoid long stub line lengths
6.1.1 Network with a junction box
In a network with one passive junction box, all the cables will be viewed as stub lines since there is no trunk
line. Keep the stub lines as short as possible.
Stub
Junction box
Device 1
Device 3
Device 4
Device 5
Device 6
Device 7
Device 8
Device 2
1 m
1 m
1 m
1 m
1 m
1 m
1 m
1 m
Fig.14: Network with a junction box
6.1.2 Network with Y-connectors
A network with Y-connectors without stub lines (directly connected to the M12 connector of the device)
Device 1
Device 3
Device 4
Device 5
Device n
Device 2
1 m 5 m 7 m 8 m 1 m
YYYY
Fig.15: Network with Y-connectors without stub lines

Type büS
Detailed project plan 1
19
Network with Y-connectors and stub lines
1 m 5 m 7 m 8 m 1 m
0.5 m 0.5 m 0.5 m 0.5 m
Y
Device 1
Device 3
Device 4
Device 5
Device n
Device 2
YYYY
Fig.16: Network with Y-connectors and stub lines
6.1.3 Mixed network
In a mixed network, it is important to indicate the total length of the cables. This includes the length of all
trunk lines and stub lines.
Junction box
Device 4
Device 5
Device 6
Device 7
Device 8
Device 3 1 m
1 m
1 m
1 m
1 m
1 m
5 m 1 m 3 m
10 m
Device 9
Device 10
Device 2
5 m
Device 1
Device n
YYY
0.5 m 0.5 m 0.5 m
Fig.17: Mixed network

Type büS
Technical know-how
20
7 TECHNICAL KNOW-HOW
7.1 Termination resistors
Termination resistors are located on each side of the trunk line. The impedance is approximately 60 Ω
between CAN-HIGH and CAN-LOW.
Exception: In a large network with long stub lines, the longest distance between two devices should be es-
timated. It is also recommended to choose the longest distance in a network that consists of more than one
passive junction box.
CAN_H
CAN_L
Node 1 Node 2 Node n
. . . . . . .
Termination Termination
Fig.18: Termination resistors
7.2 Connection for diagnostics
We recommend providing a free connection for diagnostics. A port of the junction box or an extra Y-con-
nector in the network can be used. This access is important for fast diagnostics with büS stick and the
Bürkert Communicator software.
Furthermore, it can be used for measurements with external tools, e.g. GEMAC CANBUS Tester 2. In this
case, a measurement connection at both ends is recommended.