Frame – Texas Instruments Laser And Motor Drives DRV8811EVM User Manual
Page 11
Time
Base
A
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R
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Pulses Per Sec ond
www.ti.com
Windows Application
The DRV8811_RD customer EVM allows for the possibility of coordinating step rates such that
accelerating and decelerating profiles are achieved. Both acceleration and deceleration are controlled by
the same parameters, acceleration rate and time base.
When the motor starts, it always starts at the slowed pulses per second (PPS) speed (62 pulses per
second). The controller will accelerate the motor in order to reach the PPS speed. Acceleration rate is an
8-bit number (0 to 255) that gets added to the current PPS speed and time base is an 8-bit number (0 to
255) that specifies how many milliseconds will elapse from one speed increase to the next. Once the
specified PPS speed has been achieved, the acceleration stops.
Figure 8. Step Rate
When the motor is commanded to stop, the inverse of the description above occurs.
The Windows Application frame to control speed, acceleration and deceleration, as well as motor start and
stop, looks as portrayed in
.
Figure 9. Speed Control Frame
SLVA344A – July 2009 – Revised September 2009
Laser and Motor Drives
11