Applied-motion STR2 Manuel d'utilisateur télécharger pdf (Page 19)

STR2 Hardware Manual

920-0059B

1/30/2014

Step 4: Load Inertia

e STR drives include anti-resonance and electronic damping features which greatly improve

motor performance. To perform optimally, the drive must understand the electromechanical

characteristics of the motor and load. Most of this is done automatically when you select the

motor using switches B1, B2 and B3. To further enhance performance, you must set switch B4

to indicate the approximate inertia ratio of the load and motor. e ranges are 0 to 4X and 5 to

10X. e motors table shown in Step 1 of this section include the rotor inertia of each motor.

Please divide the load inertia by the rotor inertia to determine the ratio, then set switch B4 as

shown. For assistance in calculating the load inertia of your application contact our Applications

department.

Step 5: Step Size

e STR2 requires a source of step pulses to command motion. is may be a PLC, an indexer,

a motion controller or another type of device. e only requirement is that the device be able

to produce step pulses whose frequency is in proportion to the desired motor speed, and be

able to smoothly ramp the step speed up and down to produce smooth motor acceleration

and deceleration.

Smaller step sizes result in smoother motion and more precise speed, but also require a

higher step pulse frequency to achieve maximum speed. e smallest step size of the STR2 is

1/20,000th of a motor turn. To command a motor speed of 50 revolutions per second (3000

rpm) the step pulses frequency must be 50 x 20,000 = 1 MHz. Many motion devices, especially

PLCs cannot provide step pulses at such a high speed. If so, the drive must be set for a lower

number of steps per revolution. Six dierent seings are provided in the STR2 drive, as shown

in the table on the next page.

5-10X

0-4X

1 2 ... 14 15 16 17 18 19 20 21 22 23 24 ... 37 38

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Applied-motion STR2 Manuel d'utilisateur Page 19