Articles...
The Future of CAN / CANopen and the Industrial Ethernet Challenge
by Wilfried Voss, President esd electronics, Inc USA
Industrial Ethernet technologies are a formidable challenge to CANopen as the low-cost
industrial networking technology of choice. Ethernet technologies will
eventually replace the majority of CANopen applications, at least in regards to
new developments.
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CAN for Critical Embedded Automotive Networks
by Lars-Berno Fredriksson Kvaser / IEEE
Over the past decade, electronic systems have gradually replaced mechanical
ones in cars and trucks. The forces driving this replacement have
mainly included environmental demands that require advanced electronic
engine and driveline control in addition to reduction of wire-harness
size. In the mid-1980s, Bosch and Intel developed a serial network
protocol, called controller area network (CAN), and implemented this in
silicon chips for supporting hardware. The CAN protocol transfers
information between electronic control units (ECUs) in vehicles. In the
early 1990s, Mercedes was the first company to introduce CAN in
standard cars. Since then, the CAN protocol has proved to be an
inexpensive, robust solution for automotive control networks and is now
well established and used in all types of vehicles.
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Extending the reach of your CAN application
by Wilfried Voss
One of the ingenious features of CAN, the bit monitoring, contributes not only to the enormous reliability of Controller Area Network, but it is ironically also responsible for its biggest
drawback, the limited physical distance of the CAN bus. Restricted physical distance is definitely an issue especially for applications such as elevators, security systems and other building
technologies. The one and only way to extend the usable bus length without compromising the reliability is to lower the baud rate. In cases where reliability is not the main focus, e.g.
diagnostics and low priority messaging, a CAN bus can be extended as far as the reach of the Internet.
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Data Sheets:
CAN Repeater
CAN Bridge
CAN Ethernet Gateway
CAN Remote Frames on Recall
by Wilfried Voss
Experience over the years has uncovered some oddities in the CAN protocol - which are naturally not covered by any official document - and one of them has lead to the call to avoid CAN
remote frames. In August of 2005 CAN-in-Automation (CiA) released (but not promoted) their application note 802 - "CAN remote frame - Avoiding of usage".
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CAN or Ethernet – A Design Aspect
by Wilfried Voss
When it comes to the design of a system with distributed intelligence, i.e. a networked multi-processor system, the first question that a design engineer faces is the choice of an appropriate
networking technology that best meets the design specific requirements. CAN (Controller Area Network) and Ethernet are both very popular choices, especially when a certain level of
vendor-independence, i.e. the avoidance of manufacturer-specific technologies, is an important aspect.
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Selection Criteria for CAN Higher Layer Protocols
by Wilfried Voss
Even though extremely effective in automobiles and small applications, CAN alone is not suitable for machine automation, since its communication between devices is limited to only 8 bytes.
As a consequence, higher layer protocols such as CANopen for machine control, DeviceNet for factory automation and J1939 for vehicles were designed to provide a real networking
technology that supports messages of unlimited length and allow a master/slave configuration.
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CANopen Device Profiles
by Wilfried Voss
The ultimate goal of CANopen is to provide OEMs and end users a certain
level of manufacturer independence by providing standard device
profiles for a continuously increasing number of controls. This paper
will provide an overview of the CANopen specification (DS-301, DSP-302)
and will explore in more detail the device profiles for generic I/O
modules DS-401), drives and motion control (DSP-402), and IEC 61131-3
programmable devices (DS-405).
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