CAN wiring ground?
Many CAN transceivers will tolerate a “ground offset;” a difference in ground potential between network nodes. That offset is specified as between -2 and +7 volts, but transceiver IC often tolerate larger offsets, such as ±12V for the Microchip MCP2551 device.
What if there is no house ground wire?
If the box is not grounded, you have two choices: Run a ground to the box. This would mean running a new wire back to the panel (could be bare copper, but if you’re doing the work may be better just to run a new wire – 14/3 would be the best), which could mean opening up drywall. Wire the fan without ground.
CAN lines shorted together?
There are two different communication lines used in a CAN bus, the CANH and CANL, high and low respectively. These two lines have multiple ways that they can be shorted. They can be shorted to ground, shorted to VCC, or shorted together.
CAN ground be resistant to network?
Damage from lightning or welding typically causes a short to ground on one or both CAN lines. Unplug the connector from the device. Measure resistance on the connector pins of the device between CAN HI and CAN LOW. The resulting resistance should be between 28k – 50k ohms.
Do you need a ground for a CAN bus?
But for normal CANbus, you need a ground. Yes, a common ground is need. A can transceiver has a maximum common mode voltage. If the common mode voltage of the differential CAN signals exceeds the maximum, then the transceiver will not be able to recognize the bits.
Do you need common ground for CAN transceiver?
Yes, a common ground is need. A can transceiver has a maximum common mode voltage. If the common mode voltage of the differential CAN signals exceeds the maximum, then the transceiver will not be able to recognize the bits.
Why is my CANbus not communicating with other devices?
All devices on the network must share the same ground. Different ground potentials between devices will lead to common mode voltages forming on the CANBUS. These will distort communication signals and can lead to damaged equipment and may also pose a safety hazard.
What should the voltage be on a CAN bus?
Normally the voltage should be between 2.0 V and 4.0 V. If it is lower than 2.0 V or higher than 4.0 V, it is possible that one or more nodes have faulty transceivers. For a voltage lower than 2.0 V please check CAN_H and CAN_L conductors for continuity.