Controller Area Network (CAN)
The Hytec CAN Eurocard product range includes a multi-function
I/O Control board, a 16-input Intelligent 12-bit ADC board and an
Intelligent CAN-PC Interface.
Hytec is currently developing a new modular range of intelligent
CAN products for industrial control and data acquisition.
CAN Product Overview
Controller Area Network (CAN) is an ISO approved standard for a
low cost real time communication protocol. It has a relatively high
transmission speed (up to 1Mbps). It is fault tolerant and robust system.
CAN was initially developed by Robert Bosch for in-vehicle data transfer
and was defined in 1984. Silicon became available in 1987 and CAN was first
used in cars in 1992.The draft international standard was introduced in 1991
and this became a full standard (ISO 11898) in 1994.
CAN systems can be configured very efficiently and flexibly with respect
to their data exchange. Many hardware features have been transferred to the
software level. Its serial bus structure gives two advantages over parallel
bus systems; increased transfer reliability even over large distances and more
favourable costs. The serial bus usually consists of a single twisted pair.
It has a multi-master priority based bus access which uses carrier sense
multiple access with collision detection and non-destructive arbitration.
(CSMA/CD + NDA). It has system wide data consistency.
CAN allows multicast reception with time synchronisation error detection
and error signalling. It has automatic retransmission of corrupted messages
and allows distinction between temporary errors and permanent failure of
nodes with autonomous switch-off of defective nodes. A node can make a
remote data request. Other features of CAN are functional addressing and
automatic retransmission of corrupted messages. The signalling uses
non-return to zero bit encoding and allows full isolation of the interconnecting
wires. The standard covers the first two layers of the ISO OSI seven layer model,
(physical and data link layers).