Contents
CAN bus distance between nodes?
The electrical characteristics of the CAN bus cable restrict the cable length according to the selected bit rate. You can use cabling up to 250 meters with the baud rate of 250 kbit/s. The maximum bus length with a bit rate of 10 kbit/s is 1 km, and the shortest with 1 Mbit/s is 40 meters.
CAN bus capacitance?
Connector and suppression device capacitance can vary widely and media distributed capacitance ranges from about 35 pF/m for low-capacitance, shielded-twisted-pair cable to 70 pF/m for backplanes.
CAN bus physical layer?
The Physical Layer is the basic hardware required for a CAN network, i.e. the ISO 11898 electrical specifications. It converts 1’s and 0’s into electrical pulses leaving a node, then back again for a CAN message entering a node.
CAN bus reflections?
Reflections cause ringing in the signal level and to remove them, it is necessary to absorb the energy. This can be done by placing a resistor at the end of the CAN-bus with the same value as the impedance of the cable.
CAN node be distance?
Node to node distance is about 60 mm.
Why CAN you only use 120 ohm?
Terminal resistors are needed in CAN bus systems because CAN communication flows are two-way. The termination at each end absorbs the CAN signal energy, ensuring that this is not reflected from the cable ends. Hence 120 Ohm termination adaptors are considered the standard for CAN bus.
CAN bus 60 ohm?
CAN Bus Termination. There should be a 120-ohm termination resistor located at each end of the bus to prevent signal reflections. When you measure the resistance between CAN HI to CAN LOW on a wiring harness you should measure 60 ohms. This measurement should be conducted with the device power off.
What are the requirements for a CAN node?
Details of a Typical CAN Node The High-Speed ISO 11898 Standard specifications are given for a maximum signaling rate of 1 Mbps with a bus length of 40 m and a maximum of 30 nodes. It also recommends a maximum un-terminated stub length of 0.3 m.
What should be the nominal impedance of termination resistors?
The termination resistors on a cable should match the nominal impedance of the cable. ISO 11898 requires a cable with a nominal impedance of 120 Ω; therefore, you should use 120 Ω resistors for termination. If you place multiple devices along the cable, only the devices on the ends of the cable need termination resistors.
Is the single wire can interface available on ni-Xnet?
Single-wire CAN transceivers are available only on NI-XNET software-selectable PCI and PXI interfaces. Because single-wire CAN networks are already terminated, you should use only nonterminated CAN cables for connecting NI single-wire CAN interfaces to single-wire CAN devices and networks.