Illegal data value (Modbus Exception)

What does 3 mean?

A value contained in the Modbus query data field is not an allowable value for the server (drive). This indicates a structural fault in the remainder of a complex request, such as an incorrect implied length. It does NOT mean a submitted data item is outside an application's expectation, as the Modbus protocol doesn't interpret specific register values.

Additional Steps

Steps 1–2 are listed in Priority Fix.

1. 3

   Ensure that any implied data lengths in the request are correctly calculated and transmitted.

2. 4

   Refer to the Modbus protocol specification and drive manual for correct data formatting for the function.