Using CAN IC to replace RS-485 IC

Electrically, CAN and RS-485 are different. In the CAN recessive state, the differential voltage can be zero; this is not a valid RS-485 signal level. However, many RS-485 receivers have built-in fail-safe logic that interprets an undriven bus as logic one, and a bus without such logic is supposed to have fail-safe biasing resistors with the same effect. So if you wire the bus so that the CAN dominant state (CANH > CANL) corresponds to RS-485 logical zero (A < B), then a CAN transceiver on a RS-485 bus might actually work.

The simplest solution would be to replace all transceivers so that, on the electrical level, the bus uses CAN parameters. (Simple CAN transceivers do not care what protocol you're using.)

Chinh,

As Clemens said, the physical layers between RS-485 and CAN are different and thus the voltage levels are different, and not compatible. There are ways to make it work, but the simplest answer would be to use all CAN transceivers for an Automotive application.

Regards,

Eric Hackett