Sveba-Dahlen COF

What does Sveba-Dahlen COF mean?

The SD-180's Schneider frequency converter has detected an interruption on the CANopen communication bus. The control is no longer receiving valid cyclic messages from one or more nodes on the bus. This fault halts normal drive operation to prevent uncontrolled behavior resulting from lost coordination between the converter and other system components.

Symptoms

• Drive stops or refuses to start, displaying COF on the touchscreen or converter display
• Loss of speed reference or torque commands from the PLC or master controller
• Other CANopen network nodes may also report communication timeouts simultaneously
• Oven conveyor or mixing bowl motor becomes unresponsive to control inputs
• Intermittent fault that may clear briefly then return, especially under vibration or thermal cycling

Common causes

• Interrupted or broken CANopen bus cable between converter and master node
• Loose or corroded D-Sub/RJ45 CANopen connector at the converter or control panel
• Incorrect or missing bus termination resistors at one or both ends of the CANopen network
• Node address (MAC-ID) conflict or incorrect baud rate setting on the converter
• Faulty CANopen option card installed in the Schneider frequency converter
• EMI interference on the bus cable caused by inadequate cable shielding or routing near high-voltage conductors

Diagnostic steps

1. 01

   Inspect CANopen cabling

   Power down the SD-180 and visually inspect all CANopen bus cables for cuts, pinches, or loose connectors. Reseat all connectors firmly and check for corrosion on pins.

2. 02

   Verify bus termination

   Confirm that 120-ohm termination resistors are installed at both physical ends of the CANopen network. Missing or duplicate terminators are a leading cause of COF faults.

3. 03

   Check node address and baud rate

   Using the SD-180 touchscreen or drive keypad, verify that the converter's CANopen node ID and baud rate match the settings configured in the master PLC or control system. Mismatches will prevent bus communication.

4. 04

   Test bus continuity

   With all nodes powered off, use a multimeter to measure resistance across CAN-H and CAN-L at the converter connector. A correctly terminated network should read approximately 60 ohms; deviations indicate a wiring or termination fault.

5. 05

   Reset and monitor the fault

   After correcting any wiring issues, perform a fault reset via the touchscreen and power-cycle the drive. Monitor the CANopen network status in the drive's diagnostic menu to confirm stable communication before returning the oven to service.

When to call a professional

Escalate to a licensed Sveba-Dahlen service technician if the COF fault persists after verifying cabling, termination, and node settings, or if the CANopen option card in the Schneider converter is suspected to be faulty. Replacing internal converter option cards or reprogramming network parameters beyond standard drive menus requires factory-level training to avoid damaging the SD-180 control system.