DSI Comm Loss

What does F081 mean?

Communications between the drive and the Modbus or DSI master device have been interrupted. This is a specific loss of data exchange over the serial DSI link, preventing the drive from receiving commands or sending status, which can cause it to fault or stop. The drive's response is governed by parameter C125 [Comm Loss Action].

• Broken or loose DSI communication cable (e.g., RJ45) between the drive and the Modbus master.
• Incorrect DSI communication parameters (e.g., P7-00 to P7-05) configured on the drive or Modbus master (e.g., baud rate, parity, address).
• Termination resistor (e.g., 120 Ohm) missing or incorrectly placed on the DSI network segment.
• DSI master device (e.g., PLC, HMI) is powered off or not actively polling the drive's DSI address.
• Electrical noise interference on the DSI cable due to improper routing near power cables (e.g., VFD output lines).

Click steps to track your progress.

1. 1

   1. Verify physical DSI cable continuity between the drive's DSI port and the Modbus master using a multimeter (e.g., pin-to-pin resistance < 1 Ohm).

2. 2

   2. Confirm drive's DSI parameters (P7-00, P7-01, P7-02, P7-03, P7-04, P7-05) match Modbus master settings (e.g., baud rate, parity, drive address).

3. 3

   3. Measure resistance across DSI+ and DSI- terminals at the last device on the network; it should be approximately 60 Ohm with two 120 Ohm resistors (or 120 Ohm if only one).

4. 4

   4. Cycle power to the DSI master device (e.g., PLC processor) and monitor communication status indicators.

5. 5

   5. Disconnect DSI cable shield from ground at one end (e.g., drive end) to mitigate ground loop currents, if applicable.