No. 5 - March 28, 2025

A word from the CiA Managing Director

(Source: Adobe Stock)

There is still some confusion regarding terminology: What are “frames”, “packets”, “segments”, “messages”, and “parameters”. Often this is caused by historical “misuse” of terms in standards, specifications, guidelines, data sheets, etc.

  • Frame – This is an entity of the OSI data link layer. In CAN (ISO 11898-1), there are five frame formats standardized: CBFF (classic base frame format), CEFF (classic extended frame format), FBFF (FD base frame format), FEFF (FD extended frame format), and XLFF (XL frame format).
    NOTE: Do not use “CAN packet”, “CAN segment”, or “CAN message” instead of “CAN frame”. Never use the term “CAN message frame”.
  • Packet – This is an entity of the OSI network layer.
    NOTE: Normally, there is no dedicated network layer specified in CAN-related higher-layer protocols.
  • Segment – This is an entity of the OSI transport layer as standardized in the ISO 15765 (also known as ISO TP) series, in CANopen (segmented SDO), in J1939-21/22 (BAM and CM), in ISO 11783-3 (Isobus), etc.
    NOTE: ISO 15765 uses the term “packet” instead of “segment”.
  • Message – This is an entity of the OSI application layer as standardized in CANopen (PDO message, EMCY message, etc.) and J1939-based specifications (Parameter Groups and Diagnostic Message), for example.
    NOTE: “Message” is the OSI application layer payload, which is normally mapped into the CAN data field, but can also be mapped to the CAN-ID field.

“Messages” may contain one or more “parameters”. “Parameters” are entities of the application as specified in (device, application, and interface) profiles. In the automotive industry, often the term “signal” is used instead of “parameters”. This can cause confusion with physical (analog) signals. This is, why CiA avoids using the term “signal” as a synonym of “parameter”. CiA distinguishes between “process data parameter”, “configuration parameter”, and “diagnostic parameter”. SAE also has started to change the term “signal” to “parameter”, where appropriate in J1939 documents.

In my opinion, it is very valuable to use terms correctly. Laboratory slang can cause misinterpretation and confusion, in particular, for newcomers. But, it will be a long way, to substitute the correct terms in all data sheets, handbooks, and documentation, including standards and specifications. Nevertheless, we should start using correct terminology, now.

Embedded World Nuremberg

Around 32000 visitors from more than 40 countries participated in this international tradeshow. CiA showed on its booth three CAN FD light demonstrators by Bosch, ST Microelectronics, and Vector. There was a lot of questions and discussions about this commander/responder approach. Some of the 1200 exhibitors presented CAN-related products and services. Many of them have migrated to CAN FD capable hardware. Increasingly, CAN SIC transceivers are implemented. CiA has managed a CAN-related session on the accompanying conference with about 1900 attendees.

CAN Newsletter magazine

The March issue provides two CAN physical layer related articles. Magnus Hell (Infineon) explains in detail the design of CAN XL networks. Marc Itrich (esd) discusses how CAN SIC transceivers can improve the signal quality. There is also an application report about fleet electrification of Danish police cars.

SIG radar sensor: Inaugural meeting

CiA invites its members to the inaugural online meeting of the SIG (special interest group) radar sensor. On request of ifm, Kuebler, and Pepperl+Fuchs, CiA will establish a new SIG developing a device profile for radar sensors. This HLP-independent (higher-layer protocol) device profile specifies process data, configuration parameters, and diagnostic information. Additionally, the SIG will standardize the mapping to CANopen and J1939 application layers. It is intended to specify dedicated J1939 parameter groups (PGs) and pre-defined CANopen process data objects (PDOs).

The inaugural meeting of the SIG radar sensors takes place on May 6 (13:00 to 15:00, UTC+2). Non-members are welcome, too. Registration is obligatory to get the Zoom link.

Wanted: CANopen motor for skeletons

For a project, a CiA 402 compliant motion controller is needed. The developers are looking for flat 3-phase BLDC motors, able to provide a torque of 100 Nm after a gear box. This means, a torque of 1 Nm to 2 Nm at the motor output shaft is sufficient. The developers can use an appropriate ratio reducer. If your CANopen product meets this requirement, please inform CiA office.

CiA Member Days presentations and CiA GA minutes

The CiA General Assembly (GA) took place on February 25, 2025 as a part of the CiA Member Days event in Frankfurt (Germany). The CiA General Assembly minutes can be downloaded by members from the CiA website. The CiA Member Days presentations are available for member companies on request.

CiA technology day: CAN-based networking in mobile machinery

On April 30, CiA organizes an online technology day comprising several presentations in English language. The 4-hours event starts at 13:00 (UTC+2). Here, CiA engineers and experts from CiA member companies give an introduction into CiA documents addressing mobile machines (CiA) and CAN-based energy management options (CiA). CAN-based control networks for mobile machines (Microcontrol) as well as functional safe sensors for CAN-based control networks (CiA) are on the agenda. Cybersecurity for CAN-based mobile machines is also a topic presented by Embedded Systems Academy (EmSA). Further, CiA informs about the ISO 25200/DIN 4630 body application networks and gives an insight into the future of CAN in mobile machine control applications.

The participation is free-of-charge. Registration is obligatory and is possible via email.

Meet CiA at Bauma 2025

From April 7 to 13, CiA exhibits at the Bauma trade show in Munich (Germany) on a joint stand with nine member companies. The co-exhibitors are Baumer, Cattron, Emotas, esd electronics, Kvaser, Microcontrol, Softing Automotive Electronics, Wachendorff Automation, and Xtrack. Main topic is CANopen in construction, earth-moving, and mining machinery. Migration to CANopen FD, functional safety, and cybersecurity are other hot topics on the agenda.

Meet CiA in hall A2, stand 337 to discuss these and further CAN-related issues. It is also possible to schedule in advance an appointment via email.

News ticker

+++ Epec (Finland) has introduced the SLX8X control unit featuring a Codesys runtime software, which will be shown at the Bauma tradeshow (hall A2/booth 426). +++ Syslogic (Switzerland) has developed the RPC RS A4NA rugged computer implementing the Jetson Orin Nano processor by Nvidia. +++ Kunbus (Germany) offers the RevPi Connect 5 module coming with an optional CAN FD interface. +++ VIA Technology (Taiwan) has launched the fanless AMOS-9100 host controller powered by an Nvidia processor. +++

CiA activities

New CiA members since the last CCN

  • Geksan (RU)
  • Odosolutions (SE)
  • P Dahl Elektronik & Data (SE)
  • Zaber Technologies (CA)

CiA has 719 members (March 28, 2025)

New video on Youtube

CiA Product Guides

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Editors: Olga Fischer, Holger Zeltwanger (responsible according to the press law)
Advertising: Birgit Ruedel (responsible according to the press law)

CAN in Automation (CiA) e. V.
Kontumazgarten 3
90429 Nuremberg (Germany)
Tel. +49-911-928819-0
AG Nuremberg VR 200497

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