CY545 Stepper System Controller
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CHAPTER 5 - MOTOR CONTROL COMMANDS
Motor Control Commands
The motor control commands are used to set the operating conditions for running the stepper
motor, and to actually move the motor. Various commands set relevant parameter values, and
two commands cause actual motor motion. In addition, the JOG signal may be used to move
the motor manually at any time.
Set Stepping Rate
Three commands set up the basic step rate functions for the CY545. They are:
R Rate
F Rate
Set maximum step rate
Set initial step rate
S Slope.
Set acceleration slope
The rate parameters for Rate and FirstRate are single byte values that select the initial and
maximum step rates for the motor. These parameters are pointers into the CY545 Rate Table,
shown in a later section of this manual. The actual step rate in steps per second comes from a
combination of the Rate Table and the operating frequency of the CY545. The step per second
values of the Rate Table have been computed for a crystal frequency of 12 MHz. The use of
other frequencies causes a linear scaling of the rates, and may be derived by multiplying the
given rates by Fcy/12, where Fcy is the actual crystal frequency (in MHz) used for the CY545.
The slope parameter for the Slope command determines how quickly the CY545 accelerates
and decelerates while stepping. It is also a single byte value, and should range from 1 to 255.
Slowest accelerations are selected by small values of slope, while fast accelerations use larger
values for slope. In practice, you must experiment with the slope parameter value to determine
the optimal acceleration for your specific application. Initial values in the 175 to 225 range might
be tried, with adjustments made as required.
Acceleration and deceleration are symmetrical, and are controlled by the single slope
parameter. For small values of slope, the CY545 can take a very large number of steps to go
from the initial rate to the maximum rate. If the distance to travel is too short to allow the CY545
to reach the maximum rate, it will perform a partial acceleration, reaching the highest possible
rate under the current slope parameter, before having to decelerate to stop at the target
position.
Set Count and Direction
Three commands set relative mode values for the CY545. They are:
N Num24
Set number of steps
Select CW direction
Select CCW direction
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© 2002 Cybernetic Micro Systems
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Chapter 5 - Motor Control Commands
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