Hardware Installation Manual of the IES Series
11
HWMN-IES-R20121030
Micro step Resolution Selection
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 micro step resolution for the system:
·
Consider the MAX speed needed, MAX input frequency of driver and MAX output frequency of the controller.
·
Micro step resolution of 1600 pulses/revolution (8 micro step) is suitable for most application.
·
Micro step resolution of greater than 1600 only increases smoothness but not resolution.
Current Control Detail
Leadshine
’
s IES integrated step servo motor is integrated with a high-resolution 1,000-line optical incremental
encoder. That encoder can send the real-time shaft position back to the integrated drive of the IES. Like traditional
servo controls, the drive can automatically adjust the output current to the motor. The output current ranges between
the holding current and the close-loop current. When there is no pulse sent to the drive, the IES goes into idle mode
and the actual motor current is determined by the holding current percentage (similar to
“
idle current
”
of open loop
stepper drives). In normal working mode, the IES monitors the actual shaft position all the time. The current
outputted to the motor changes dynamically based on the tracking error between the actual position and the
commanded position.
Low holding current can reduce motor heating however also reduces the holding torque which is used to lock the
motor shaft at standstill. It is recommended to determine the holding current by whether or not there is big vibration
at start-up and how much lock torque is required, based on your actual applications.
Fine Tuning
Leadshine already loads default current-loop parameters and position-loop parameters. Those default parameter
values have been optimized. They should be good enough for most industrial applications, and there is no need to
tune them. However, if you want to fine tune the IES for best performance for your applications, Leadshine also
offers tuning software, ProTuner, which allows you to adjust those current-loop and position-loop parameters (see
software manual).
