Most standalone CAN controllers available today are connected to the host system by eight or sixteen bit wide parallel buses. Write and especially read accesses to such peripheral devices are very slow compared with the cycle time of modern CPU's. This paper discusses the resulting performance bottleneck and shows a solution, using a CAN controller implemented in an FPGA, that can use bus master DMA.

Different governments around the world are calling for massive reductions of CO2 emission. In the EU by the year 2020, the average CO2 emissions per passenger car should fall to 95 g/km. Hard measures and challenging technological advances are required. The imposed EU limits are not achievable only with the optimization of conventional technologies. New methods dealing with an efficient and flexible power management are an urgent need. Partial networking is one of these methods. It is intended to make it possible for a node or a sub-network to be woken individually by means of dedicated and predefined messages. When its tasks are not required it is in selective sleep mode. With this approach, a saving of almost one gram CO2 per km is a realistic estimation for a middle-range car. Since the beginning of 2010 a working group called SWITCH has been working to make partial networking for CAN bus systems an environmental and commercial success. The outcomes documents specified in the framework of this working group are currently in the ISO process. Different concepts for partial networking as well as the achievements and standardization activities taken over by the SWITCH group will be presented in this speech.

This paper describes the design, manufacturing and installation of a CAN bus Lamp control system that eventually consisted of 765 nodes running a customized protocol updating nodes at 24Hz. A second network, with 6 nodes running the CANopen protocol, was used for diagnostics and bus configuration. Each LED Lamp node has a single processor that controls 36 Red, Green, Blue and White LEDs. The application software, written in Delphi and running on a PC sends messages via USB to a control computer containing 5 CAN bus channels. The 5 CAN bus channels were further broken into 3 sets of 50 nodes using a CAN Bridge. Additionally, with a USB to CAN controller the CAN open link into the Bridges was used to monitor the status of each of the 15 groups of 50 CAN nodes.What made this project unique was the time frame from concept to the design, construction and installation of this one of a kind product. Some of the problems, included rainy weather, component and cable failures are discussed.

A steering control system based on CAN-bus technology was developed in accordance to safe operations for vessels on sea. With CAN-bus technology we reduced the efforts of cabling with highest reliability on sea. The paper describes the steering and navigation system of vessels with respect to automatic control. All data (reference values, measured values, alarm handling, configuration values) of a steering system with certain devices (e.g. Rudder, Feedback Unit, Gyro, Autopilot, etc.) are transmitted via CAN-Bus in real time. A short introduction explains the problems of steering vessels. A central component of the steering system is the autopilot. Its main task is to keep the ship on heading given by the helmsman or an Electronic Chart Display information system (ECDIS). The main part describes the design of the required controller. Closing the paper with measurement results of the autopilot demonstrate exemplary the safe operations.

CAN is one of the most successful wired serial data communication protocols both in terms of volumes and in terms of acceptance across industry branches considering the past twenty years. It is the predominant bus protocol in today’s and upcoming vehicles. This paper outlines protocol success factors, CAN protocol usage at GM/Opel, CAN benefits, and protocol improvement needs from an automaker point of view.

Motion control includes drives technologies and control systems with integrated software platforms. Currently, the drives are represented by pneumatic and electric technologies. A challenge for the suppliers of Motion Control solutions is to propose the common platform (hardware/software) which allows the easy use of pneumatic and electric drives. Example of this platform could be hybrid valve terminal where the coexistence of these two technologies was possible thanks to: - CAN bus used as the embedded backbone for communication with all elements of Motion Control system - Common Data Profile for pneumatic and electric drives

Since Linux 2.6.25 (issued 2008-04-17) the Linux mainline kernel supports the network protocol family PF_CAN providing standardized programming interfaces for CAN users and CAN driver developers. This paper provides an overview of the implemented technologies and challenges to integrate the Controller Area Network into a non-real-time multiuser/multitasking operating system. Due to the standardized network driver model for CAN hardware a wide range of different CAN controllers and System-on-Chip CAN IP cores are supported by Linux out-of-the-box. In opposite to usual embedded CAN ECUs the Linux networking system is designed to handle multiple CAN applications using multiple CAN busses at the same time. The integration of the CAN infrastructure into the networking stack allows to implement CAN-specific transport protocols like ISO 15765-2 or high-performance CAN frame gateways inside the operating system context. Finally the paper discusses solutions for expected prioritization issues when executing multiple CAN applications and summarizes requirements for Linux-preferred CAN controller concepts.

Ever increasing bandwidth requirements in automotive networks impede the applica- bility of CAN due to its bit rate limitation to 1 MBit/s. To close the gap between CAN and other protocols, we improve CAN in two ways: (i) support of bit rates > 1 MBit/s and (ii) support of payloads > 8 byte per frame. We achieve this with a new frame for- mat where we can switch inside the frame to a faster bit rate for (i) and use a different data length coding for (ii). This new protocol is called “CAN with Flexible Data-Rate” or CAN FD. CAN FD protocol controllers are also able to perform standard CAN com- munication. This allows to use CAN FD in specific operation modes, e.g. software- download at end-of-line programming, while other controllers that do not support CAN FD are kept in standby. This paper presents the CAN FD frame format with additional bits in the control field to enable the new options and the new CRC sequence to secure longer frames with the same Hamming distance as in the existing CAN protocol. The configuration options for the two bit rates are explained in detail. We provide measurements of the upper limits for the bit rate, using the first hardware implementation of a CAN FD protocol controller and standard CAN transceivers.

During recent years, the discussion about power saving had and has different aspects. One of them has been to save power in CAN applications. The mechanisms, which can be used either on physical layer or on the microcontroller, will be discussed within the article.

In this article, we present a new method for describing CANopen network topology. A new format using GraphML, an XML-based graph format, is introduced. By using a subset of GraphML along with CANopen-specific new elements and attributes, topology of single as well as multiple CANopen networks can be captured in a well established graph format with existing tool support. The new format is specified in a manner that allows CANopen design applications to adopt it while providing a mechanism for fallback in unsupported software. Methods for extending the format to contain other CAN- and CANopen-specific data as well as transforming the GraphML- based network structure to other formats are described. Finally, the implications of the introduced method and format are discussed.

During recent years, not only CAN and UART communication have been important for microcontrollers, also Ethernet was gaining importance. Therefore, microcontrollers for industrial application do not only need an intelligent CAN module, they also need smart ways of connecting to other protocol engines. This article shows one solution to do so.

One intriguing aspect of networked nodes is the option to allow their firmware to be remotely updated in the field. Some CANopen Device Profiles have even made this a requirement. The updating process in the target is handled by a dedicated piece of firmware, the CANopen bootloader. A failure of the bootloader can have severe consequences, from necessary power cycles over direct mechanical interaction with the device up to having to replace the node. For deeply embedded nodes that are out of reach, for example in deep-sea applications, such a failure can even be catastrophic. Therefore, in this crucial piece of software, security and reliability of operation deserves special consideration. Combined with resource constraints common in bootloaders, these unique requirements ask for a dedicated rather than a common off-the-shelf CANopen implementation. This paper discusses the security aspects of such an implementation in regards to software engineering, safe coding practices and operation flow.

SocketCAN, the official CAN API of the Linux kernel, has been included in the kernel more than 3 years ago. Meanwhile, the official Linux repository has device drivers for all major CAN chipsets used in various architectures and bus types. SocketCAN offers the user a multiuser capable as well as hardware independent socket-based API for CAN based communication and configuration. In this paper we will at first focus on motivating the socket based approach used in SocketCAN and continue with a discussion about its supporting and opposing arguments and current limitations especially in comparison with other available Linux CAN stacks. We proceed with a close look at the structure and duties of a generic CAN driver. The usage of the most widespread userspace protocol for sending and receiving raw CAN frames (SOCK_RAW) is illustrated with a small program. The paper concludes with some remarks on the outlook of upcoming contributions and enhancements such as an isotp and a J1939 protocol implementation.

This paper describes the development of a family of sub-fractional horse-power electric motors with integrated CANopen interface. The integration of motor and control unit makes elegant and compact drive solutions for numerous industrial applications possible. The drives decrease wiring effort in the system and space requirement in the electronics cabinet. Additionally, the integrated bus interface of these motors enables an efficient automatic final test in the motor production line without the need for cost intensive test stands.

In August, ETAS and Robert Bosch Engineering and Business Solutions (RBEI) jointly published BUSMASTER, a free open source PC software for the design, monitoring, analysis, and simulation of CAN bus systems. The software can be downloaded from rbei-etas.github.com/busmaster/. The current BUSMASTER version is based on the preceding software tool CANvas, conceptualized, designed and developed by RBEI. It offers import filters for network description files and simulation programs compliant with standard industry formats. For CAN connections, hardware from different vendors is supported. The BUSMASTER software project, sponsored by RBEI and ETAS, is open to contributions from research and industry. The software can be developed and managed with free software tools. Thanks to the modular architecture, third-party software developers can easily add new functions to the software. The license also permits the provision of proprietary add-ons, which can be dynamically linked to the open source core. The openness of the project managed by the sponsors provides for flexible modification and extensions regarding bus systems, protocols, and hardware interfaces. In addition, it will facilitate short cycles in the solution’s onward development.

This paper addresses the analysis of control performance for vehicle active suspension via Controller Area Network (CAN) based on full vehicle model. The dynamic model of the system is developed based on four sets of suspension which constitutes 14 state variables communicated through six CAN nodes. The Linear Quadratic Regulator (LQR) technique is used to reduce heave, pitch and roll variation to achieve desired performance of active suspension. The simulation work is performed by using Matlab/Simulink with TrueTime toolbox. Various system performances are analyzed by varying CAN data speed, CAN loss probability, nodes sampling time, clock drift and scheduling techniques. Based on the analysis, the setup of the proposed CAN network for the system meet the system requirements.

Use of Linux in embedded systems has become vastly popular. On hardware platforms, the ARM processor cores have a strong foothold. To address the needs of Linux-based embedded automation systems, Wapice has implemented custom high- performance CAN driver architecture. The Wapice Custom Can Driver (WCCD) is targeted for embedded Linux and optimized for ARM-based platforms. In this paper, we present our findings made during the development process and methods we used to optimize the driver performance. Performance measurements, comparing the effects of optimizations, are also presented. We discuss how CAN message buffering algorithms affect the bus performance, show how Linux kernel version affects the interrupt latencies, and present challenges related to SPI-based CAN transceiver chip usage. To evaluate our design, we present the performance of Wapice Custom CAN driver (CPU load, CANmsg/s) and compare it against SocketCAN and LinCAN implementations. We also show results of a brief study on porting WCCD to other processor platform. Based on the results, we conclude that WCCD is an extremely high-performance embedded Linux CAN driver which can match or outperform the compared existing implementations.

"The demands on the availability of data in the cabin and cockpit have been increasing in recent years. Right there is the application of new field bus systems. These must be suitable for the harsh environment in aircraft and therefore shown to be sufficiently robust. In the area of network based aircraft systems, the CAN-bus has emerged as a future technology. Through standardization, industrialization of that technology is now ahead for the aviation industry. In the Technical Working Group ARINC 825, in- dustry partners of the aircraft industry, led by the two largest aircraft manufacturers Airbus and Boeing, developed a standard that will change the interconnection of sys- tems in aircraft further. The standard describes guidelines and ""best practice"" to be observed by the system developers and the aircraft manufacturer for seamless inte- gration into the aircraft and smooth interaction of the equipment."

Nowadays we discover a changing focus at car development. To handle the growing system- and testing complexity, simulation comes to the fore. This process is supported by innumerable tools and methodologies with the goal to speed-up and simplify the development of new automobiles and technology. The tools are mostly highly specialized and dedicated only to a tiny area of the development process or on the other hand are such generic that they cannot be used without customization. In the area of subjects of C&S group and its customers it occurs very often, that the validation of real and simulation-based networks and components must be integrated into the development processes of the customer. The experience of C&S group in collaboration with its customers has shown, that the validation of simulation-based network descriptions gains more and more acceptance. Therefore C&S group has developed a new automation tool to validate network topologies, like they are used in automotive, avionics and industry areas, with the aid of a new model-based testing methodology. This paper shall present the new automation tool and shall generally enlighten the model-based testing methodology with practical examples.

TREPEL, the leading manufacturer in the cargo high loader market, introduced a new product line, the Challenger tractor. These new vehicles are able to handle pushback, maintenance towing and repositioning of any commercial aircraft, up to the new Airbus A380, and almost every military airplane. The Challenger fleet is designed to perform under tough working conditions as well as extreme climatic conditions. The ballasted version of Challenger 700 can handle weights up to 600 tons. Instead of usual controls and instruments, the dashboard is equipped with a Janz Tec panel-PC. This is the main control center of the tractor and the display of all relevant data provided by the internal CAN bus.

There is today more than 20 years of experience in automotive CAN applications, and CAN has certainly proven very successful as a robust, cost effective and all-around network technology. But the use of CAN in vehicles is evolving, in particular because of more complex and heterogeneous architectures with FlexRay or Ethernet networks, and because of recent needs like hybrid, electric propulsion or driver assistance that involves more stringent real-time constraints. Besides, there are other new requirements on CAN: more fine-grained ECU mode management for energy savings, multi-ECU splitted functions and huge software downloads. In parallel, safety issues request more and more mechanisms to protect against potential failures and provide end-to-end integrity. The development process is also evolving with the advent of multi- domain cooperation, Autosar, ISO2626-2 and the always shorter time-to-market requirements. In this landscape, CAN has now to be used at much higher bus load level than in the past, and there is less margin for error. What does it imply in terms of verification and validation? What are the characteristics of the communication stacks that should be paid attention to? This article is intended to shed some light and share our views on these issues.

Shortly after the Controller Area Network developed by Bosch was introduced in cars, it started to be used in industrial communication networks. The most successful Higher Layer Protocol which is based on CAN is still CANopen. CANopen tried as good as possible to use the technical parameters given by the underlying CAN chips. Now, after decades, Bosch has extended the CAN protocol to be much more faster. It seems to be possible to overcome the most criticized parameter in CANopen - bus speed and available bandwidth. The paper discusses the new opportunities for CANopen given by the »CAN with Flexible Data-Rate«.

"The trend to add more distributed electronics to applications also applies to taxis, emergency response vehicles, governmental vehicles and cars with special controls for handicapped drivers. However, in modern cars it becomes more and more difficult to add electronics, as build-in electronics and airbags are a closed system and all space around the dashboard is occupied. Access to the internal vehicle networks (IVN) is a delicate matter. For safety reasons, the car manufacturers are reluctant to allow direct access to ""everyone"". CiA447 defines an open vehicle network with which car manufacturers provide limited access to their internal networks. As all accesses go through a gateway, the gateway can limit the access to those parameters considered ""safe"". As an example, where supported, buttons and displays of the car can be used by CiA 447 devices. However, the ultimate control remains within the car. In an emergency situation, the car could still override / overwrite the display with required warnings. To allow easy and simple network connections, a standard connector, extended plug- and-play mechanisms as well as power-down and wake-up controls are defined."

In the light of going “Green”, one of today's major challenges for carmakers is improving the fuel efficiency to reduce the vehicle's fuel consumption and its carbon footprint [1]. The efforts to achieve greater efficiency can be obtained in different fields. Within this paper we want to highlight different methods on energy savings in the field of In Vehicle Networking using CAN bus. Starting with System-Basis Chips (SBC) with an on-board DC/DC convertor for optimized power use compared to classical system-basis chips with linearly regulated supplies. Its deployment in the powerful Body Control Modules and other modules with more power hungry micro-controllers will bring an important gain in fuel consumption. A further step is the use of Partial Networking to put part of the network in a low power mode. In the method described in ISO 11898-6, selective wake-up is used. After a discussion of this method, an architecture based on CAN repeater chips will be proposed as an alternative solution to obtain significant power savings.

Traditional way of working with distributed systems has focused only to application software development of each node independently of each other. Typically signal connections are described in manually maintained documentation, which rarely fully conform CANopen. Result is potentially faulty documents, which need to be checked during build process. The main problem is a lack of system design – faulty or inconsistent signal connections, parameter access paths and values can not be detected as long as file formats are not violated. Further problems are met in system assembly and service, where faulty configuration files potentially lead to invalid system behavior. This paper presents the main methods to help managing the signal and parameter transfers in system level. Because CANopen is a system integration framework, all necessary services already exist – they just need to be used. First half of the paper describes how CANopen supports consistent signal validity monitoring and plausibility checking. Another half of the paper describes how parameter accesses and parameter attributes can be managed by CANopen mechanisms. Main result is that CANopen intrinsically supports the system design and required parameter and signal abstractions can be transferred from CANopen system designs to IEC 61131-3 application projects in a standardized way.

Hydraulic valves have been driven by separate valve control electronics for decades. The tradition is becoming obsolete due to ever increasing performance, controllability, maintainability and re-usability requirements of the target systems. However, there are still a lot of functionally constrained fully hydraulic systems which need to be upgraded first to electrically controlled. There are also huge number of simple proprietary control systems needing upgrade from proprietary to standard technologies and components. Especially for such kind of systems, it is important to achieve easy and straightforward upgrade path from use of proprietary valve amplifiers into coil-mounted drivers with current-controlled valve. Further step is replacing separate valves and drivers with intelligent hydraulic drives. It is also important to utilize commonality between lower- and higher performance drive solutions. This presentation shows hands-on case examples how the presented system integration challenges can be solved with standard CANopen devices according to device profiles for general-purpose I/O-devices (CiA-401) and hydraulic drives (CiA-408). The main conclusion is that commitment to CANopen actually enables not only the required approaches, but also manufacturer and device independence with large number of interchangeable devices. Another significant result is that the lowest level applications can be implemented just by integrating standardized devices, without application software project.

Device specific profiles provide important advantages when implementing intelligent network structures for machine control. In these supplementary standards (device and application profiles), the behaviour and parameters of standardized devices or applications are specified. For proportional valves, hydrostatic pumps, and hydrostatic transmissions the common device profile CiA 408 has been specified, which is based on the bus independent device profile ‘Fluid Power Technology’ of the VDMA (Verband Deutscher Maschinen- und Anlagenbau). The initial version of CiA 408 was published in 2003. This profile has been implemented by many manufacturers of hydraulic components to provide a common, vendor-independent way of hydraulic device integration into a CANopen system. Since then, the functionality of hydraulic devices has increased: new control modes and sensor interfaces have been defined and a lot of feedback from the field has been collected during the last years. In order to take account of these developments, the fieldbus independent device profile ‘Fluid Power Technology’, was updated in 2011 which resulted in the new version 1.6. This report will give a short overview and point out the changes and new features of the derived CAN bus specific device profile CiA 408.

More than 25 years ago Robert Bosch developed CAN with the needs and require- ments of the automotive industry. CAN is now in use for over 20 years in the automo- tive industry and every major international carmaker has adopted it for most of their product lines. Almost any new introduced car makes use of CAN. But there is no standardized higher-layer protocol in use by these manufacturers. There are several attempts in standardization like namely OSEK, but they are not very widely adopted. Together with different carmakers CAN in Automation has developed one defined in- terface based on the international standardized higher-layer protocol CANopen. It is intended to be used in special purpose cars like for example taxi, police, emergency response vehicles, and cars for disabled persons.

This presentation will introduce new features of the todays Real Time Oscilloscope generation to debug serial busses, e.g. CAN. New capabilities not just offer decoding functions but allow triggering on the content itself. Specific identifiers, payload, even failure indications like error checksums or error frames can be detected and recorded within seconds.

"Widespread use of electronic equipments in vehicles has proved increasing importance of vehicular electric network performance. The reliability of the equipments, to some extent, depends on the reliability of its network. Therefore, the enhancement of vehicular electrical network is vital for automotive electronics industry. This paper presents a novel method to improve the reliability of ""vehicular electric network"" by using an online monitoring system. Voltage, current and network noise are selected factors, measured and sent to the central processing unit for analysis. The network information is measured by means of node sensors for which details are given. Having collected information across the network, fuzzy models of each region is developed based on its circuit profile. The outputs achieved by this model, determines the situation of vehicle power network and possibility of any fault occurrence in each area could readily be predicted. In practice, fault prediction helps to increase network reliability."

CAN bit timing and synchronization play an important role in ensuring performance of CAN network. A misplaced sampling point can lead to one of the transmitters going error passive. Computation of right timing parameters require detailed knowledge of CAN bit synchronization and also may lead to complexities owing to number of input parameters & a variety of possible solutions. The engineer should choose the optimum Sampling Point and Time Quanta so as to ensure robust CAN implementation. Purpose of this paper is to present a simplified method, such as a ready reckoner, to compute Time Quanta using a two-step computation method. During the first step, Pre- scalar values for each Time Quanta are calculated using CAN Frequency and Baud-rate. This provides a set of permissible Time Quanta’s. During the next step, Sampling Point and Oscillator Tolerance are calculated for each permissible Time Quanta. This yields output variables such as Time Segment 1 & 2 and Synchronization Jump Width which are subsequently used to configure the CAN controller. In addition, this paper attempts to analyze trend of Oscillator Tolerance and Sampling Point for various values of Time Quanta.

The CANopen application profile CiA 454 Energy Management Systems was designed for light electric vehicles (LEVs). In the course of a revision, now the application spectrum was expanded to stationary standalone systems for PV hybrid energy supply.

With CAN-based systems being used in manifold applications that require continuous operability, also under harsh environmental conditions and extended service-cycles, the verification of CAN operability is essential. Especially, the direct detection of failure sources enabling thorough maintenance before systems may fail. This presentation shows how the use of enhanced CAN specific test tools in combination with common measurement devices like Digital Signal Analyzers is key to solve typical failures in CAN systems. Often these failures require significant time and effort to solve: e.g. detecting faulty configured devices leading to multiple bit- rates or use of same CAN-IDs by several nodes in a network or the how to detect the device that destroys any messages by its primary error-flag. Furthermore various possibilities will be discussed which can be used to improve the robustness of CAN networks. These possibilities can help harden a network against failures on the physical layer and misbehavior of devices in order to avoid a breakdown of the complete network.

Nowadays, CAN buses are standard building blocks, not only in automotive area and industrial automation, but to an increasing degree in safety sensitive areas, including medical environments, aircraft industry and even in space. With the elevated safety requirements there's a rising need for verification, simulation and testing. In general, CAN controllers available on the market are unable to generate CAN traffic containing errors or violating CAN ISO 11898 standard. This paper describes a simple and effective approach using flexible FPGA technology to inject errors into CAN buses. Adding rather small error injection units to a CAN controller within an FPGA provides means to not only generate all kinds of errors on CAN bus, but also to interact with and modify ongoing CAN traffic, at the cost of little more than standard CAN hardware. Error injection units feature several injection modes, such as CAN arbitration, time triggered or pattern matching, and can be combined to accommodate more complex scenarios.

Outlining the Need When looking at various CAN applications, an extreme set of such are in complete contrary to the mass-automotive scale. Many CAN usages are in rather small quantities. In such a category various defense systems find their classifications. When considering defense CAN design, some aspects remain almost as in mass- quantity scale (such as: reliability, upgradeability). However, few are of premium concern. Driven from the very small quantities scale (in the hundreds to thousands), defense CAN designs often rely on an easily modifiable hardware – FPGA components. Furthermore, niche defense needs put some varying requirements over CAN controllers and logic that are hard to find in the common CAN controller chips (standalone for sure, but also in the CPU - embedded CAN peripherals). One example of importance here is the implementation of redundancy (deployment of 2 or even 3 CAN media-hardware for the purpose of a single-redundant CAN network). Last but not least, defense designs do not put a great emphasis on hardware components cost. Thus, FPGA are very welcome there, with an abundance of headroom, providing feasibility to the previously mentioned attributes.

Contactless interfaces are essential to different applications which rely on physical robustness and / or high modularity and movability. This work presents a solution for direct conversion of CAN signals for contactless capacitive coupling over an air gap. The coupling distances are short (in the range of less than 1 mm), but can be extended by a supporting rail which contains coupling electrodes and conductors to deliver the signals also over larger distances. A modulation scheme is implemented to maintain the functionality of dominant and recessive bit status. No additional controller is needed the transceiver module replaces the CAN transceiver typically added to any microcontroller.

CANopen is mainly used in connecting devices in embedded networks. During the development process of the ECU (electronic control unit), the maturity of the embed- ded system increases with testing in early stages. A good approach is to test before the first prototype is available. Step by step, the test environment is expanded and is able to simulate CANopen bus communication behavior. Application behavior is also added to the test environment. This paper shows the methods available at different development stages and their application. Starting with a simple network simulation that just integrates EDS files, a test environment grows as the development advances. Application behavior is added by hand-written C modules, libraries or even MATLAB/Simulink models. Finally, the simulated ECU and finished ECU use the same application code. To obtain a complete Hardware-in-the-Loop simulator, additional hardware is required to simulate sensors and actors. Testing is possible in parallel to every development step. Test procedures may range from simple interactive elements to a fully automated test system.

Event Scheduled CAN (ESCAN) is an open source, scheduling protocol for CAN. The aims of the protocol are discussed, including the ability to optimise the available bandwidth over CAN and enable maximum bus loading as well as providing a worst case determinism for message reception. These advantages include a simple to implement basic protocol stack, no specialist hardware requirements needed to support the protocol other than a TTCAN compliant CAN controller (this is so that the retransmission of CAN frames can be disabled). The protocol also uses a low amount of CPU and memory overhead to transmit its schedule control data resulting in high potential bus loading at all CAN bit rates. In this paper, the protocol itself will be introduced along with a brief comparison against other scheduling protocols in the literature. Preliminary experimental performance data for ESCAN is collected and compared with a TTCAN Level 1 implementation showing benefits. Finally an analysis will be conducted on the effect of using ESCAN as a scheduling layer for the CANopen protocol.

As the CAN standards specified in the ISO 11898 series cover just the lower layers (physical and data link layer) of the OSI reference model, the network system designer has to deal additionally with the functionality of the higher-layer protocols (from the network to the application layer). In many CAN applications, just the application layer functions need to be implemented. From the beginning, there was some standardiza- tion of CAN-based higher-layer protocols requested, in order to save software invest- ments by means of reusing programs and routines developed for different applica- tions. The paper provides an overview of “open issues” to be considered and solved by the higher-layer protocols, and discusses the different solutions introduced by standardized application layers. It is not intended to compare the standardized solu- tions but to describe the different approaches in respect to system design require- ments.