Texas Instruments Evaluation module for DRV8828 DRV8828EVM DRV8828EVM 데이터 시트
제품 코드
DRV8828EVM
#Accel_Steps =
Number_of_Steps
AccelerationPercentage
100
?
#Deceleration_Steps =
Number_of_Steps
DecelerationPercentage
100
?
Start Speed PPS
Start Speed PPS
Desired Speed PPS
Total Number of Steps
Deceleration
Steps
Acceleration
Steps
Steady State Steps
UART Mode
Since in a previous application note (
) we implemented 256 degrees for a microstepping engine,
we can take this design one step further. The DRV8828EVM and DRV8829EVM have been programmed
to divide a full step to up to 512 degrees of microstepping.
to divide a full step to up to 512 degrees of microstepping.
The microstepping resolution frame gives the user the option to change the full step divider factor so that
microsteps from half step to 512 degrees of microstepping are obtained. Selection is done by pressing
one of the radial boxes. Only one option can be made at any given time. If the motor is not moving,
changing the selection only applies to the next time the motor starts moving. If the motor is rotating,
change of direction will be observed instantaneously.
microsteps from half step to 512 degrees of microstepping are obtained. Selection is done by pressing
one of the radial boxes. Only one option can be made at any given time. If the motor is not moving,
changing the selection only applies to the next time the motor starts moving. If the motor is rotating,
change of direction will be observed instantaneously.
4.5
Move Steps Frame
If the user desires to move the stepper a certain number of steps, this can be easily accomplished by
using the move steps function. Parameters from the other frames are reused and its utilization is as
explained previously. Three new parameters have been added to properly control the limited number of
steps actuation.
using the move steps function. Parameters from the other frames are reused and its utilization is as
explained previously. Three new parameters have been added to properly control the limited number of
steps actuation.
Number Of Steps: How many steps/microsteps the controller will issue.
Accel % or Acceleration Percentage: A percentage from the total number of steps which will be used to
accelerate the motor stepping rate. The result is a number of steps which will be allocated to the
acceleration portion of the motor actuation.
accelerate the motor stepping rate. The result is a number of steps which will be allocated to the
acceleration portion of the motor actuation.
(3)
Decel % or Deceleration Percentage: A percentage from the total number of steps which will be used to
decal the motor stepping rate. The result is a number of steps which will be allocated to the deceleration
portion of the motor actuation.
decal the motor stepping rate. The result is a number of steps which will be allocated to the deceleration
portion of the motor actuation.
(4)
In move steps mode we specify a total number steps which we want the motor to move so that a
pre-determined distance is achieved. However, depending on the desired speed, it may be imperative to
accelerate and decelerate the stepping rate, or errors in motion may occur. Since the total number of
steps is in itself a variable, how much we want to use for acceleration and deceleration must also vary
accordingly.
pre-determined distance is achieved. However, depending on the desired speed, it may be imperative to
accelerate and decelerate the stepping rate, or errors in motion may occur. Since the total number of
steps is in itself a variable, how much we want to use for acceleration and deceleration must also vary
accordingly.
The microcontroller firmware gathers the parameters and computes a portion of steps from the total
amount, which will be utilized for the acceleration portion of the profile and the deceleration portion of the
profile. The remaining steps are used to move the step at the reached speed, which (depending on how
parameters were chosen) could or could not be the desired speed.
amount, which will be utilized for the acceleration portion of the profile and the deceleration portion of the
profile. The remaining steps are used to move the step at the reached speed, which (depending on how
parameters were chosen) could or could not be the desired speed.
Figure 10. Move Steps
13
SLMU002
–
June 2011
DRV882x Evaluation Modules
Copyright
©
2011, Texas Instruments Incorporated