DM805-AI Hardware Installation Manual
20
HWMN-DM-R2011060
Selecting Operating Mode
Mode
SW7
SW8
Description
0~5V Speed
on
on
Analog 0-5V Speed Mode
Lo/Hi Speed
off
on
Low and High Speed Mode
External POT
on
off
External Potentiometer Speed Mode
Pulse/Direction
off
off
Pulse and Direction Position Mode
Note
: Remove power supply before changing operating mode.
Microstep Resolution Selection
In Pulse/Direction mode, microstep resolution is selected by SW4 and SW5. The stepper motor moves one step when one pulse is
applied to the stepper drive. If microstep is 1, the step angle is a full step which is 1.8 degree for 2-phase stepper motor and 1.2 degree
for 3-hpase stepper motor. Microstep can be taken as the divisions of one full step. For example, stepper motor moves half of the full
step when the microstep is 2. For 2-phase stepper motor and drive, we have the following formula to calculate the microstep resolution,
or pulse counts of one motor shaft revolution:
Microstep
solution
Microstep
200
Re
The motor speed can be calculated as follows:
solution
Microstep
Frequency
Input
Pulse
RPS
Speed
Motor
Re
)
(
When selecting the drive’s microstep resolution for the system:
Consider the MAX speed needed, MAX input frequency of driver and MAX output frequency of the controller.
1600 pulses/revolution (8 Microstep) is suitable for most application.
>1600 pulses/revolution only increase smoothness but not resolution.
For digital driver, Microstep resolution is not important.
Current Settings
Dynamic current setting
For a given motor, higher drive current will make the motor to output more torque, but at the same time causes more heating in the
motor and drive. Therefore, output current is generally set to be such that the motor will not overheat for long time operation. Since
parallel and serial connections of motor coils will significantly change resulting inductance and resistance, it is therefore important to set
drive output current depending on motor phase current, motor leads and connection methods. Phase current rating supplied by motor
manufacturer is important in selecting drive current, however the selection also depends on leads and connections.
