AMCI SD4840EK, User Manual

Page: 19 / 104

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
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19
REFERENCE 2
M
OVE
P
ROFILES
Definitions
Units of Measure
Distance
Every distance is measured in steps. When you configure the unit, you will specify the number of steps you
want to complete one rotation of the motor shaft. It is up to you to determine how many steps are required to
travel the appropriate distance in your application.
Speed
All speeds are measured in steps/second. Since the number of steps needed to complete one shaft rotation is
determined by your programming, it is up to you to determine how many steps per second is required to rotate
the motor shaft at your desired speed.
Acceleration
The typical unit of measure for acceleration and deceleration is steps/second/second, or steps/second
2
. How-
ever, when programming an SD4840EK, all acceleration and deceleration values must be programmed in the
unit of measure of steps/second/millisecond.

To convert from steps/second
2
to steps/second/millisecond, divide the value by 1000. This must be done
when converting from a value used in the equations to a value programmed into the unit.

To convert from steps/second/millisecond to steps/second
2
, multiply the value by 1000. This must be
done when converting from the value programmed into a unit to the value used in the equations.
Motor Position
Motor Position is defined in counts, and its limits are based on the data format you choose when configuring
the unit. The default multi-word format limits the Motor Position range from -32,768,000 to +32,767,999. If
you choose the thirty-two bit double integer format, the range is -2,147,483,648 to +2,147,483,647. In contin-
uous rotation applications, you should choose the double integer format.
Home Position
The Home Position is any position on your machine that you can sense and stop at. There are two ways to
defining the Home Position. The first is using the Preset Position command to set the Motor Position register
to a known value. The second method is using one of the
Find Home
commands. If you use the unit’s
Find
Home
commands, the motor position and encoder position registers will automatically be set to zero once the
home position is reached. Defining a Home Position is completely optional. Some applications, such as those
that use the SD4840EK for speed control, don’t require position data at all.
Count Direction
Relative moves with a positive offset will increase the motor position register reported back to the host. Some
of the moves, such as the Jog Move, have a positive and negative command. A positive command, such as the
CW Jog Move command, will result in an increase in the motor position value. If the motor is wired as shown
in this manual, these moves will result in clockwise rotation when looking at the motor shaft.
When a move command is sent to the SD4840EK, the module calculates the entire
profile before starting the move or issuing an error message. This chapter
explains how the profiles are calculated and the different available moves.