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Menu 5
Mentor MP Advanced User Guide 75
Issue Number: 4 www.controltechniques.com
Rotating Autotune (Pr 5.12 = 2, 3 or 4) is only available when tacho or encoder feedback are selected.
If this parameter is set to a non-zero value, the drive is enabled and a run command is applied in either direction the drive performs an autotune test.
All tests that rotate the motor are carried out in the forward direction if Pr 1.12 {di12, 0.47} = 0 or the reverse direction if Pr 1.12 {di12, 0.47} = 1. For
example, if the test is initiated by applying run reverse (Pr 6.32 = 1) the test is performed in the reverse direction. The test will not start unless the
drive is disabled before the test is initiated by applying the enable or run, i.e. it will not start if the drive is in the stop state. It is not possible to go into
the stop state if Pr 5.12 {SE13, 0.34} has a non-zero value.
When the test is completed successfully the drive is disabled and will enter the inhibit state. The motor can only be restarted if the enable is removed
either from the enable input, or Pr 6.15 is set to zero or from the control word (Pr 6.42) if it is active.
Static autotune for current loop gains
When this operation is performed, the drive will estimate the following, with respect to the selected motor map, and store the values:
Motor constant (Pr 5.15)
Continuous proportional gain (Pr 4.13)
Continuous integral gain (Pr 4.14)
Discontinuous integral gain (Pr 4.34)
Back EMF set point (Pr 5.59)
Armature resistance (Pr 5.61)
Flux loop P gain (Pr 5.71)
Flux loop I gain (Pr 5.72)
Spinning autotune for rated field compensation factor and motor saturation break points
When this operation is performed, the drive will estimate the following, with respect to the selected motor map, and store the values:
Motor saturation break points (Pr 5.29, Pr 5.30), and Rated field compensation factor (Pr 5.74) by spinning the motor at 25 % of it’s Base speed
(Pr 5.08 {SE08, 0.29})
Spinning autotune for inertia measurement
• The drive attempts to accelerate the motor in the forward direction up to 3 /4 x rated load rpm and then back to standstill. Several attempts may
be made, starting with rated torque/16, and then increasing the torque progressively to x
1
/
8
, x
1
/
4
, x
1
/
2
and x 1 rated torque if the motor cannot
be accelerated to the required speed. 5s acceleration time is allowed during the first four attempts and 60 s on the final attempt. If the required
speed is not achieved on the final attempt the test is aborted and a tuNE1 trip is initiated. If the test is successful the acceleration and deceleration
times are used to calculate the motor and load inertia which is written to Pr 3.18.
•Pr 3.18 is saved to EEPROM.
The calculated value of inertia is dependant on the value of the motor torque per amp (Pr 5.32). If the inertia is used for automatic speed loop gain
setup the calculated gains will not be affected because Kt is also used in these calculations and any inaccuracy cancels out.
The test algorithm attempts to remove the effect of any load on the motor other than the torque required to accelerate and decelerate the motor, i.e.
friction and windage losses, static torque load etc. Provided the average torque during acceleration and the average torque during deceleration are
the same the effect of the additional torque is removed and the inertia value is calculated correctly.
Spinning autotune for motor saturation break points
When this operation is performed the drive will perform an estimation of Motor saturation break points (Pr 5.29, Pr 5.30) by spinning the motor at 25 %
of its Base speed (Pr 5.08) with respect to the selected motor map and store the values.
5.12
{SE13, 0.34}
Autotune
Coding
Bit SP FI DE TE VM DP ND RA NC NV PT US RW BU PS
111
Range 0 to 4
Default 0
Update rate Background read
Value
Autotune function
0 None
1 Static autotune for current loop gains
2 Spinning autotune for rated field compensation factor and motor satura-
tion break points
3 Spinning autotune for inertia measurement
4 Spinning autotune for motor saturation break points
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