Parker HPD2N, Руководство пользователя, Страница: 41 / 125

Parker Hannifin S.p.A. - S.B.C. Division HPD N User’s Manual
38
BEFORE STARTING
Before starting observe figure 1.
Fig. 1
The graph shows system response to a square wave speed reference. Channel 1 (Ch1) is
speed and channel 2 (Ch2) is motor current. The channel 1 oscilloscope probe is connected to
terminal 9 of X2 and channel 2 to terminal 7 of X2. The V/div scale and the timebase are not
mentioned as they may vary considerably.
CALCULATING Pr16
The value of Pr16 should be calculated before enabling the drive. Pr16 defines system
gain. To convert Pr16 into degrees for rated torque use the formula:
ac
= ⋅
Pr
Pr
33
16
28
where ac is
the stiffness angle. Obviously, before the formula can be used Pr33 must be set to motor rated
current. To evaluate ac correctly we shall consider that, if the driven machine transmission is
rigid (not flexible) and there is no transmission backlash, the optimal stiffness angle could be
around 4 degrees. If the transmission is not sufficiently rigid it may be necessary to reduce
gain. If motor torque has been selected to achieve steep acceleration ramps, while dynamic
torque changes in normal operation are minimal, stiffness angles of 20, 30 or 40 degrees are
acceptable without negatively affecting performance. If you encounter difficulty in choosing
the most appropriate stiffness angle, start from 10 degrees, which is the default value when
using a motor with the same rated current as the drive.
Now enter the calculated value for Pr16 and start the motor with a square wave reference
signal (pay attention when setting the reference amplitude and frequency to avoid problems in
the case of limited stroke axes). On the oscilloscope note that the response changes as Pr17 is
altered. Lowering Pr17 will allow you to approach system response as shown in figure 2.