CAN bus signal monitoring using the DL850V Yokogawa Meters & Instruments Corporation

Leading-edge Technologies What is CAN? Controller Area Network Developed by BOSCH in 1983. It is a de facto standard protocol, being used for communication between ECUs in a vehicle. It is used for data communication such as speed, RPM, break status, diagnosis information. It is widely being used for not only for vehicle but also power, vessel, railroad, medical equipment, FA, elevator, etc. Master Slave Serial communication Leading-edge Technologies

Leading-edge Technologies Merit of using CAN Cutting Harness………low-cost, simple-design Cutting weight………..more economical Differential signal……noise reduction (safety) Error detection……….higher reliability Wire Harness Using CAN Simple Light weight complicated Leading-edge Technologies

Leading-edge Technologies (Reference) Example of in-vehicle network For Multi-Media For Fault-diagnosis (controlled legally) Fault-diagnosis “CAN” diagnosis tool Sub-Network For Power Train Chassis MD/CD changer Lamp Instrument panel Keyless Door Switch Sensor Squibb Air-bag Control For Safety For Body Control Gateway Tire Pressure Engine Steering The source: Renesas Electronics Corporation (Japan) Leading-edge Technologies

Leading-edge Technologies (Reference) CAN regulation Both datalink layer and Physical layer are defined. Application Layer Data Link Layer (ISO11898, ISO11519-2) Acceptance, Filtering (1:1, 1:n communication) Overload (not ready yet) Notice Resend when an error is occurred Presentation Layer LLC Session Layer Processed by CAN controller Frame Generation (Data, Remote, Error, Overload frame) Bus monitoring, Error detection and notice Acknowledgement Arbitration Transport Layer MAC Network Layer Data Link Layer Physical Layer (ISO11898, ISO11519-2) Physical Layer Bit, Timing, Synchronization, Resynchronization, Communication speed Processed by CAN Transceiver Bus characteristic, Driver, etc. Controlled by Software Controlled by Hardware OSI basic reference model In addition to ISO-defined standards, there are some other CAN-regulated standards such as SAE J2284, J2411. Leading-edge Technologies

Leading-edge Technologies CAN bus and Node(s) ECU CAN bus = Two wire Max. 30 nodes Leading-edge Technologies

Packet signal, called “FRAME”, carried and received. Signal flow in the CAN….1 ECU CAN bus FRAME Packet signal, called “FRAME”, carried and received. Leading-edge Technologies

Signal flow in the CAN….2 Multi-master ECU CAN bus FRAME Each node can send a frame freely, also can receive a frame freely. Multi-master Leading-edge Technologies

Leading-edge Technologies Features of CAN Differential Signal Multi-master Any node can send out a message when the bus is open. The order of priority for sending Identifier field in a message determines the order of priority. System flexibility Each node has no specific address, so easy for “adding” and “removing”. Flexibility for communication speed It can be set according as a scale of network, function of system. Advanced error handling Excellent in error detection, notice and recovery Data request Any node can generate data output request for the other node. Leading-edge Technologies

Leading-edge Technologies ECU (Node) connection Communicate via differential signal (CAN_H/CAN_L) Max. 30 nodes can be connected. Terminators must be placed at the end of bus line. It is classified into two type of standards, Hi-speed CAN and Low-speed CAN. The boundary is 125kbps. The figure below shows an example of Hi-speed CAN. (Terminated by 120 ohm) Each node is connected to CAN bus via the CAN Controller and CAN Transceiver. CPU CAN Controller TX0 TX1 RX0 RX1 Transceiver Node 1 Node 2 Node N (max.30) Terminator120 ohm CAN_H ∬ Terminator120 ohm CAN Bus Line ∬ CAN_L Differential signal Leading-edge Technologies

Leading-edge Technologies CAN Topology 1. Bus type The “Bus type” is typically being used. 3. Ring type 2. Star type Leading-edge Technologies

Leading-edge Technologies A variety of frames Data Frame 　A DATA FRAME carries data from a transmitter to the receivers. Start of Frame Arbitration Field Control Field Data Field CRC Field ACK Field End of Frame The DL850V can monitor only a data frame. Remote Frame 　A REMOTE FRAME is transmitted by a bus unit to request the transmission of the DATA FRAME with the same IDENTIFIER. Start of Frame Arbitration Field Control Field CRC Field ACK Field End of Frame Error Frame 　An ERROR FRAME is transmitted by any unit on detecting a bus error. Overload Frame An OVERLOAD FRAME is used to provide for an extra delay between the preceding and the succeeding DATA or REMOTE FRAMEs. Leading-edge Technologies

Leading-edge Technologies Data Frame format (Packet structure) Arbitration Control Data CRC ACK Recessive Field Field SOF ID RTR r r DLC 0-64 EOF １ １１ Bit １ １ １ 4 (0-8 byte) 15 1 1 1 7 3 Dominant Start of Frame: Marks the beginning of DATA FRAMES and REMOTE FRAMEs. Identifier Field: Indicates the contents of message, also can be used for the order of priority for bus access.　Standard format:11bit／Extended format:29bit (DL850V supports both.) RTR: Remote Transmission Request BIT. In DATA FRAMEs the RTR BIT has to be ’dominant’. Within a REMOTE FRAME the RTR BIT has to be ’recessive’. Control Field: It includes the DATA LENGTH CODE and two bits reserved for future expansion. Data Field: The DATA FIELD consists of the data to be transferred within a DATA FRAME. (Max. 8-byte(64-bit)) CRC Sequence & CRC Delimiter 　　　: It is the frame check sequence. The CRC SEQUENCE is followed by the CRC DELIMITER which consists of a single ’recessive’ bit. Ack Slot & Ack Delemiter 　: All nodes having received the matching CRC SEQUENCE report this within the ACK SLOT by superscribing the ’recessive’ bit of the TRANSMITTER by a ’dominant’ bit. End Of Frame: A flag sequence consisting of seven ’recessive’ bits. Leading-edge Technologies

Leading-edge Technologies CAN data frame and physical data With CAN data frames, multiple data (physical data) are carried and received under a single ID. Identifier Field Data Field Ex.) b0 - - - -15 16 17 32 - - 47 48 - - 63 142h 0006h 2468h 0302h 1 Integrating revolution counter Oil pressure RPM Air cond. ON/OFF High beam indicator Leading-edge Technologies

Leading-edge Technologies Tool lineup for CAN bus ECU CAN bus FRAME DLM2000 SB5000 CANalyzer (Vector) WE7000 DL850V Leading-edge Technologies

Mainly for CAN hardware design Mainly for CAN software design Measurement targets of the CAN tools Model Target ＩＤ ＤＡＴＡ Mainly for CAN hardware design Mainly for CAN software design Leading-edge Technologies

Leading-edge Technologies The difference of observed “waveform” DLM2000, SB5000 “waveform” = Trend of “voltage signal” of the CAN bus DL850V “waveform” = Trend of “physical value(signal)” that is transmitted on the CAN bus Leading-edge Technologies

Leading-edge Technologies Simultaneous observation of CAN data and the analog signal(s) CAN bus Acceleration Sensor ECU ECU Engine ECU Strain gauge Transmission Pressure sensor Brake thermocouple CAN data Analog signals Analog Signals DL850V Leading-edge Technologies

CAN bus data monitoring Comparison and verification of actually measured signals and CAN bus signals You can check physical value trends of CAN bus data and the corresponding actually measured waveforms on the same screen at once. Multi kinds of data transmitted on the CAN bus can be monitored at the same time via a single wire. What is “CAN monitor” function? monitoring of CAN protocol communication data(signal) as an analog trend wafeform(s). 720240 CAN Frame Each signal(s) can be “extracted” from a single CAN bus line. Data Data E/G RPM Vehicle speed ECU1 ECU2 ECU3 CAN Trend of RPM Trend display Trend of speed Leading-edge Technologies

Leading-edge Technologies Sampled Data and Displayed Waveforms Extracted data is stored in memory at up to 100 ks/s while simultaneously being displayed on screen as trends. Sampled data (trend waveform data) can be saved into files. Leading-edge Technologies

Observed waveform example You can use Vector Informatik's CANdb database file (.dbc format) to indicate the field being monitored (acquired). CAN bus 1 frame Pressure sensor (analog) CAN signal (Physical layer) Current (CAN monitor waveform 1) The timing of analog signal and CAN communication signal can be checked. Pressure (CAN monitor waveform 2) Two signals transmitted by a single frame are trend-displayed as two waveforms. Leading-edge Technologies

Sub channel definition 720240 Sub channel(s) means the signal definitions of target item(s) 142h b0 - - - - - - - - - 31 00069012h 2468h 0302h 32 - - 47 48 - - 63 CH3 CH1 CH2 Up to 16CH(Signal)/port can be defined. (sub-CH) Number of sub CH ID Start bit Bit length (Note) 1 142 32 Integrating revolution counter 2 16 Oil pressure 3 48 RPM ： Note: Up to 16 of bit length can be defined by 720240 module. Leading-edge Technologies

Leading-edge Technologies Sub channel definition display (Preliminary) Signal definition setting (see the previous page) Byte Count :Target byte length Start Bit :Position of the start bit (counted from LSB) Bit Count :Target bit length Byte Order : (Big): transmitted in “from upper byte to lower byte” order (Little): transmitted in “from lower byte to upper byte” order Note: The bit data in a byte is transmitted by MSB first. Port Setup (refer to the next page) Import of setup configuration file Factor, Offset, Unit: Scaling factor and unit for converting physical value. Leading-edge Technologies

Leading-edge Technologies Port Setup （Preliminary） Bit Rate: Communication speed of the bus Sample Point: Position for detecting dominant or recessive in a single bit. Setup configuration for 720240 input port Sync Jump Width: It can be used for correction of clock cycle in a single bit for re-synchronization. Bit Sample Num: It can be used for designating the number of sample point(s). Listen Only: When it turns to “ON”, any signal(Frame, Ack) is not outputted from the DL850V. Terminator: When it turn to “ON”, the module-built-in terminator is inserted between CAN_H and CAN_L. Leading-edge Technologies

Usage of CAN db database Signal labels can be imported from CANdb database*1 Using ”Symbol Editor” free software, a message and signal can be selected(imported) from CANdb, then export as the signal labels to the DL850V. Edits CAN db file imports **.dbc Drug & Drop Definition file for exporting to the DL850V. *1：The CANdb file(.dbc) is a signal definition database defined by CANdb or CANdb++ presented by Vector Informatik. **.sbl Leading-edge Technologies

Leading-edge Technologies Outputting Frame Data (Preliminary) Single specified (defined) data frames or remote frames can be output (manually, at desired timing). Setting the condition of frame output A designated frame is output when “Execute” is set. Leading-edge Technologies

Leading-edge Technologies Model 720240 CAN Bus Monitor module main specifications 　　There are some competitive memory recorders which has CAN monitoring capability. However, the DL850V has a certain advantages over them such as higher sampling rate, easy for handling and costs. Input ports: 2 (16 signals x 2 ports) Number of Channels : 16 signals/1port Connector type: D-sub 9 pin (male), Isolated (across port and main unit, across each port) Supported protocols: Physical layer: ISO-11898 (High Speed Communication) CAN in Automation: CAN2.0B (Standard & extended message format) Bit rates: 10 k, 20 k, 33.3 k, 50 k, 62.5 k, 66.7 k, 83.3 k, 125 k, 250 k, 500 k, 800 k, 1 Mbps Max. sampling rate: 100kS/s(when using 1signal/1port) Max. 2 modules can be installed for the specified slot(s) in a single DL850V main frame. Leading-edge Technologies