CAN Communication Timeout

What does 47 mean?

This fault indicates a timeout in the cyclical communication over the CAN bus, meaning the unit is not receiving expected data from, or sending data to, another device on the CAN network within the specified time window. This can interrupt critical control and data exchange, leading to system halts, unpredictable behavior, or loss of synchronized operation. It's often related to wiring, termination, baud rate, or configuration issues on the bus, and can cause significant process downtime.

• Incorrect CAN bus termination resistors (e.g., 120 Ohms) at one or both physical ends of the CAN bus segment.
• Broken or loose wiring in the CAN bus cable (CAN_H, CAN_L, CAN_GND) connected to the MOVIFIT unit (e.g., X10 terminals).
• Incorrect CAN bus baud rate or node ID configuration (e.g., P700, P701) mismatch between the MOVIFIT and other devices on the network.
• Faulty CAN communication interface on the master device or another slave device on the network generating errors.
• Excessive electrical noise or reflections on the CAN bus due to improper shielding, cable routing, or ungrounded shields.

Click steps to track your progress.

1. 1

   Verify the presence and correct resistance (120 Ohms +/- 10%) of CAN bus termination resistors at both physical ends of the network segment using a multimeter.

2. 2

   Inspect the CAN bus cable (e.g., X10 connectors) for continuity of CAN_H, CAN_L, and CAN_GND wires and secure connections.

3. 3

   Confirm that the CAN bus baud rate (e.g., P700) and node ID (e.g., P701) parameters are identical across all devices on the network, including the MOVIFIT unit.

4. 4

   Use a CAN bus analyzer tool to monitor bus traffic, identify error frames, and check the signal integrity on CAN_H and CAN_L lines.

5. 5

   Isolate devices on the CAN bus one by one by disconnecting them to identify a faulty node that might be disrupting communication.