Can Bus Cable Capacitance

Can bus data cables.

Can bus cable capacitance.

A controller area network can bus is a robust vehicle bus standard designed to allow microcontrollers and devices to communicate with each other s applications without a host computer it is a message based protocol designed originally for multiplex electrical wiring within automobiles to save on copper but can also be used in many other contexts. 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. Iec 60332 1 2 temperature range from 40 c up to 80 c. If a voltage signal is being transmitted by a twisted pair or coaxial cable the insulation on the individual wires becomes charged by the voltage within the circuit.

2 critical spacing of can bus connections slla279a november 2008 revised january 2009 submit documentation feedback. Capacitance in cable is usually measured as picofarads per foot pf ft. Suggested cable length vs signaling rate bus length signaling rate m mbps 40 1 100 0 5 200 0 25. A cable or harness with two or more wires can also store a charge and this can affect the way the cable performs.

I have a requirement to add a module that has its own 120 ohm terminating resistor as an option to my system. I have a can bus at 125 kbit s and the wire length is less than 60 1 5 m. Capacitance describes the ability of two conductors separated by an insulating material to store charge. Controller area network physical layer requirements.

A single core cable is similar to two long co axial cylinders having dielectric in between the space. Calculation of cable capacitance. 17 minimum can device spacing on a bus with device capacitance and media. For can based communication systems like canopen flame retardant acc.

Can bus control area network is a non addressable system which treats all devices as equal allowing for fast transmission of data. Node should be avoided since the bus lines lose termination if the node is disconnected from the bus. The can bus seems to work but is there a problem with a 40 omega impedance and if so how can i test this. Since it takes a certain amount of time.

While all the types listed below are for high flexing automation applications static versions can also be supplied. It indicates how much charge the cable can store within itself. Capacitance in cables is usually measured in pf m pico farads per meter or pf ft pico farads per foot. Capacitance between conductors 1 mhz 0 pf m 40 pf m 75 pf m capacitance conductors to shield 1 mhz 0 pf m 70 pf m 110 pf m specifications can bus data cables shielded sae j1939 11.

Mechanical characteristics construction unshielded twisted pair. For each device the data in a frame is. Due to its robust nature it has been widely adopted in the automotive industry.