This post concerns the SN65HVD233 CAN transceiver device.
We use a Device Net cable with 5 conductors. Two of the conductors carry the CANH and CANL signals, and two conductors carry 24V and GND. We have had several instances in the field where a 'bad' cable causes 24V to be shorted to CANH or CANL. In that situation, what is the wattage requirement of the 120 ohm CAN-bus terminating resistor? See my attached pdf drawing that helps explain the situation.
The SN65HVD233 datasheet indicates that the "Short Circuit Output Current (Ios)" can be 250mA at 12V. In our case, the voltage is 24V instead of 12V.
The calculations in the attached document indicate that the resistor needs to be at least a 7.5W resistor, which seems very large in comparison to the 0.25W value that is recommended in most CAN-bus applicaiton notes.
Perhaps I am miss-interpreting the datasheet?