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NI ISM-7401/7402 User Manual
Figure 23.
Configuring Step Pulse Type on Switch
8
Step Pulse Noise Filter
Electrical noise can negatively affect the STEP signal by causing the drive to interpret one step
pulse as two or more pulses. This results in extra motion and inaccurate motor and load
positioning. To solve this problem, the NI ISM-7401/7402 includes a digital noise filter on the
STEP and DIR inputs. The default factory setting of this filter is 150 kHz, which is suitable for
most applications. This is set by moving switch 5 to the ON position.
Note
If you are operating the NI ISM-7401/7402 at a high number of steps per
revolution in combination with high motor speeds, you may be commanding the
drive at step rates above 150 kHz. In such cases, you should set switch 5 to the OFF
position as shown below.
Figure 24.
Configuring Step Noise Filter on Switch 5
Your maximum pulse rate equals the highest motor speed multiplied by the number of steps per
revolution. For example:
Consider the maximum pulse rate when deciding whether you must increase the filter frequency.
Self Test
If you are having trouble getting your motor to turn, use the built-in self test. When you set
switch 4 to the ON position, the drive automatically rotates the motor back and forth, two and a
half turns in each direction. Use this feature to confirm that the motor is wired correctly, selected,
and otherwise operational.
40
revs
ond
sec
------------------
20 000
steps
revs
-------------
800
kHz
=
Содержание NI ISM-7401
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