Ext I/O comm loss

What does A799 mean?

The drive generates a warning when communication to an I/O extension module fails. This indicates a disruption in the control signal flow between the drive and its peripheral I/O, potentially affecting system operation and control accuracy.

• Communication cable (e.g., RS485, Ethernet) connecting the drive to the I/O extension module is loose, damaged, or disconnected.
• I/O extension module itself has lost power (e.g., 24VDC supply) or has an internal hardware fault.
• Incorrect communication parameters (e.g., slave address, baud rate, P6-02 'Module address') configured in the drive or module.
• Electromagnetic interference (EMI) disrupting the communication signal on the bus.
• Faulty termination resistor on the communication bus, if required for the specific protocol (e.g., RS485).

Click steps to track your progress.

1. 1

   1. Power down the drive and I/O module, then verify the physical connection of the communication cable (e.g., check RJ45 or terminal block connections).

2. 2

   2. Measure the 24VDC power supply at the I/O extension module's power input terminals to ensure it is within specified limits.

3. 3

   3. Review and confirm that the communication parameters (e.g., P6-01 'Fieldbus type', P6-02 'Module address') in the drive match the I/O module's settings.

4. 4

   4. Inspect the communication cable for visible damage along its entire length, especially near cable trays or pinch points.

5. 5

   5. Check for proper termination resistors on the communication bus, ensuring they are present and correctly valued if the module is at an end of the bus.