Emtron ED5, Руководство пользователя

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EMTRON ED5 USER MANUAL WWW.EMTRON.WORLD
© EMTRON AUSTRALIA PTY LTD MARCH 2018 6
3.2 CAN Bus Wiring
The ED5 device includes an on-board CAN termination resistor. It is switchable in the
Emtron Display Editor software to allow the device to be wired at any position on the Bus
provided the termination resistor is turned off. If the ED5 is the only device connected to
the ECU in the CAN bus then it is advised to the switch the termination resistor on to
provide termination at the display end of the CAN bus. CAN Bus termination must be done
correctly by using a 120 ohm 0.25W resistor at each end of the bus system as mentioned
above. Figures 3.1 and 3.2 show possible CAN Bus Implementation examples
CAN bus wiring precautions
▪
CAN Bus High and Low are differential signals, so twisted pair MUST be used. Failing to
do so will compromise the entire CAN Bus System.
▪
In some extreme environments, shielded twisted pair may be required to help with
reliability and data integrity.
▪
The less connectors in any transmission system the better. Unnecessary connectors are
almost guaranteed to present an impedance discontinuity and hence may cause
reflections and data loss.
▪
CAN Bus termination must be done correctly by using a 120 ohm 0.25W resistor at each
END of the bus system.
▪
Maximum Stub length to a device from the main Bus is recommended at 0.3m, in
accordance with High-Speed ISO 11898 Standard specification. See Figure 3.3.
Figure 3.1. CAN Bus Wiring Example. ECU and Dash at each end with 120 Ohm Termination