F07086 — Units changeover: Parameter limit violation due to reference value change

The drive raises F07086 when a reference parameter has been changed in the system and the values that depend on it could then no longer be written in the per-unit notation. Because the re-calculation failed, the drive set the values of the affected parameters to the violated minimum limit or maximum limit, or to the factory setting, and it reports which parameter is concerned in the message value. The manuals title the message Units changeover: Parameter limit violation due to reference value change.

• A reference parameter was changed in the system, and for the parameters involved the selected value could not be written in the per-unit notation.
• The steady-state minimum limit or maximum limit — or a limit defined in the application — was violated for one of the parameters involved.

1. Read the fault value in r0949 — it displays the parameters that were not able to be re-calculated, so it identifies the parameter the drive is complaining about.
2. Look at r9450, the reference value change parameter with the unsuccessful calculation, to find the reference parameter whose change started the re-calculation.
3. Check the adapted parameter value and correct it if required; the manual lists p0304, p0305, p0310, p0596, p2000, p2001, p2002, p2003 and r2004 in connection with this fault.

• The message value carries the affected parameter: the drive shows it as Parameter: %1.
• The fault value in r0949 is described as the diagnostics parameter that displays the parameters which could not be re-calculated; no bit decoding is printed for this value.

• r0949 — fault value: shows the parameters that were not able to be re-calculated; read it first to identify the affected parameter.
• r9450 — reference value change parameter with unsuccessful calculation: points to the reference parameter whose change produced the failed re-calculation.
• p0304 (rated motor voltage, Mot U_rated) — named by the manual for this fault; check its adapted value.
• p0305 (rated motor current, Mot I_rated) — also listed for this fault; check its adapted value.
• p0310 (cylinder piston diameter, Cyl piston diam) — also listed for this fault; check its adapted value.
• p0596 (technological unit reference quantity, Tec unit ref qty) — a reference quantity named for this fault; check its adapted value after the changeover.
• p2000 (reference velocity, v_ref) — reference parameter named for this fault; check its adapted value after the changeover.
• p2001 (reference voltage) — reference parameter; check its adapted value.
• p2002 (reference pressure, p_ref) — reference parameter; check its adapted value.
• p2003 (reference force, F_ref) — reference parameter; check its adapted value.
• r2004 (reference power, P_ref) — reference parameter; check its adapted value.

The drive takes no automatic action when this fault occurs — it does not trip, so no restart sequence is needed. Once the adapted parameter value has been checked and, if required, corrected, acknowledge the fault; the acknowledgment is immediate and no special procedure is described for it.