S.B.C. Elettronica S.p.A. - Engineering Division
HPDxxN – High Power User’s Manual
33
The error value is utilised by the speed control loop to calculate (using calibration parameters) how
much current to supply to the motor.
TORQUE
: current flowing through the motor windings is converted into torque which allows the
motor to accelerate and decelerate.
GAIN
: in consideration of the typical applications of the HPD N drive, the expression “gain” in this
section of the manual refers to “stiffness”.
To understand the concept of stiffness imagine a motor
controlled by a drive with speed demand of
zero rpm.
The motor shaft will appear immobile but if we apply torque to the shaft it will rotate through an angle
that depends on the amount of torque applied.
We can then apply the rated torque of the motor and then measure the “stiffness angle” in degrees.
The resulting value provides an indication of the fidelity of the drive thus parametrised, although it is
clearly not the only fidelity indicator.
WHAT’S NEEDED
To calibrate an HPD N drive correctly we recommend using an oscilloscope with memory.
Obviously, the technician in charge must be well versed in the use of the instrument.
If it is impossible to use an oscilloscope, we illustrate, at the end of this section of the manual, an
alternative although less accurate method.
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
