PROFIBUS: timeout actual value

What does A00705 mean?

The drive has experienced a PROFIBUS communication timeout, specifically indicating that no actual data is being received from the Control Unit Processor (CUP). This can lead to a loss of real-time operational data, affecting monitoring and control if not addressed promptly, potentially halting automated processes.

• PROFIBUS master communication failure (e.g., PLC stopping, bus fault, or entering an error state) ceasing data transmission.
• Loose or damaged PROFIBUS cable connection at the drive terminal (X100) or at the master device.
• Missing or incorrectly placed PROFIBUS termination resistor (RS-485 termination) on the bus segment, causing signal reflections.
• Incorrect PROFIBUS station address (P0918) set on the drive, preventing it from responding to the master's requests.
• Intermittent electrical noise or strong electromagnetic interference (EMI) on the PROFIBUS network disrupting data packets.

Click steps to track your progress.

1. 1

   1. Verify the PROFIBUS master (e.g., PLC) is running, actively communicating, and configured correctly by checking its diagnostic LEDs or software status.

2. 2

   2. Inspect PROFIBUS cable connections at the drive's X100 terminal and the master device for proper seating, secure fastening, and physical damage.

3. 3

   3. Measure resistance across PROFIBUS Data A and Data B lines (X100 terminals 3 and 8) with power off to confirm proper bus termination (should be ~110-130 ohms with two terminations).

4. 4

   4. Check PROFIBUS address parameter P0918 in the drive and ensure it precisely matches the address configured in the PROFIBUS master's hardware configuration.

5. 5

   5. Observe the PROFIBUS communication LEDs on the drive (e.g., BF, SF) for activity or error indications, which can provide further diagnostic information.