Rockwell Automation 7000 PowerFlex Medium Voltage AC Drive (B Frame) - Classic Control - Manual (Page 244)

Commissioning 4-85
7000 “B” Frame 7000-UM150I-EN-P – June 2013
Parameter "Autotune inertia" is set to the measured inertia and
parameter "Autotune select" is set to Off. If the test is successful,
parameter "Total inertia" in "Speed Control" is set equal to
"Autotune inertia", and the speed regulator gains are recalculated. If
the test fails, then parameter "Total inertia" is not changed and a
warning is issued indicating the cause of the failure:
Reg in limit - indicates that the torque command was greater than
"Torque limit motoring" or "Torque limit braking". The measured
inertia value is invalid. Parameter "Autotune trq stp" or parameter
"Autotune spd cmd" must be set to a lower value and the test
repeated.
Tuning abort - indicates that the deviation in motor speed was
greater than 10 Hz. The measured inertia value is invalid.
Parameter "Autotune trq stp" must be set to a lower value and the
test repeated.
Inertia high - indicates that the measured total inertia is greater
than 5 seconds. This warning is intended to draw attention to an
unusually high inertia value. For a very high inertia load such as
a large fan, this may be a valid result and parameter "Total
inertia" should be manually set equal to "Autotune inertia".
However, a high inertia measurement could also be produced by
a value of "Autotune trq stp" which is too low.
Speed Regulator Manual Tuning
If it is not possible to tune the speed regulator using the autotune
function, then the step response of the speed regulator can be tuned
manually using the following procedure. To obtain accurate results,
the load torque must be steady.
1. Set parameter "Spdreg bandwidth” in "Speed Control" to 1.0
rad/sec.
Speed Control Parameter Screen
2. Set parameter "Total inertia" in "Speed Control" to an initial
value of 1.0 sec.