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Video Digital Technology

Video Digital Electronic 1
Video Digital Electronic 2
Video Digital Electronic 3
Video Digital Electronic 4
Video Digital Electronic 5
Video Digital Electronic 6
Video Digital Electronic 7

Video Digital Control Unit
Video Chiptuning 1
Video Chiptuning 2
Video Diode
Video Transistor 1
Video Transistor 2
Video Computer 1
Video Computer 2
Video Trip Computer 1
Video Trip Computer 2
Video Navigation Systems
Video Truck Tollcharge
Video On Board Diagnosis
Video Smartphone in car 1
Video Smartphone in car 2

Video Telematics 1
Video Telematics 2
Video Telematics 3
Video Telematics 4
Video Telematics 5
Video Telematics 6
Video Telematics 7
Video Telematics 8
Video Telematics 9
Video Telematics 10
Video Telematics 11

Video CAN 1 (Dis-)Advantages
Video CAN 2 Data transfer
Video CAN 3 Data integrity
Video CAN 4 Priority 1
Video CAN 5 Priority 2
Video CAN 6 Data block
Video CAN 7 Hardware
Video CAN 8 Gateway
Video CAN 9 Errors 1
Video CAN 10 Errors 2

Video LIN Bus
Video MOST Bus
Video FlexRay 1
Video FlexRay 2
Video Glass Fibre
Video Logical Connections
Video Wiring Diagrams
Video Oscilloscope 1
Video Oscilloscope 2
Video Oscilloscope 3
Video Radar Technology 1
Video Radar Technology 2
Video Fuzzy Logic
Video Data Compression
Video Reed Switch
Video Voltage Regulation
Video Clock Valve
Video History of IT
Video 7-segment Display 1
Video 7-segment Display 2

          A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

CAN-Bus - Blocks of Data

Control units keep lists of all possible messages

In the Controller Area Network Bus messages are not only dispatched, but may also be requested. A participant of the Bus requires, e.g., the controller of the temperature sensor's values. Also these requirements are programmed, like all other possible messages, into the control unit's of the Controller Area Network Bus. This takes place already in the factory. Thus, upon leaving the factory, a chip is aware, provided that it is not altered, of all the data information that it is able to provide or request. Only the contents of the data blocks are subject to change.

A correct reception of the message is acknowledged by the participants.

Another important feature of the Controller Area Network Bus is the data security. In this case data security stands for the verification of a correct reception of the data field. One possibility would be to send the sum of the digits as extra information. In this case all participants would add the bits in the data block and compare the number with the provided number. However, because it is possible that two mistakes cancel each other out, the test methods applied to the Controller Area Network Bus are substantially more complex.
If you watch more closely single messages produced on the Controller Area Network Bus, a slight protruding point at the end of every message might catch your attention. This is the bit that all participants transmit to provide feedback for the correct reception of the message. It originates from all participants, thus, it is slightly higher in voltage and stands out. The last bit is not part of the information, but comes from the other participants. This becomes especially important, when analyzing error messages. By the way, the positive feedback of one single control unit might be sufficient for the transmitter. However, without any feedback, it must repeat its message. 05/07               Top of page               Index
2001-2015 Copyright programs, texts, animations, pictures: H. Huppertz - E-Mail
Translator: Don Leslie - Email:

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