TLA Microsystems Ltd http://www.tla.co.nz 5
{C2} Half step
Each alternate step has one or two windings energised giving the motor twice
the number of steps per revolution.
When the mode is changed to or from Half step, the position, mark and speed values are
adjusted accordingly so that the motor will turn at the same rotational speed and the
mechanical positions remain unchanged.
Example: A 200 step/rev motor is being used. The current position is 3600, speed is set
at 200 steps per second and there is a mark at 1200. When the mode is changed from
full-step to half step, the speed value will be 400 (giving the same number of revolutions of
the motor per second). The current position register and the mark register will contain
the values 7200 and 2400 respectively.
D - GO TO ABSOLUTE POSITION
Syntax {Dxxxxxxxx}
At anytime after powerup, the Little Step-U keeps track of its current position in steps.
This command instructs the Little Step-U to calculate the direction and number of steps
required to move to another position and then it performs the move. At the end of the
move, the position will be the number specified in this command. The value can be any
number from -10000000 to +10000000, including 0. The number may be preceded by a
"+" or "-" as required, but must not include a comma or decimal point.
Example: If the current position is 2500, a command of {D-1000} will cause the motor to
run counter-clockwise for 1500 steps, stopping at position 1000.
E - GO TO RELATIVE POSITION
Syntax {Exxxxxx}
This command is similar to the "D" command in respect to the numeric parameter, but
commands the motor to move to a position relative to its current position. Positive
numbers are clockwise and negative numbers are counter-clockwise.
Example: If the current position is 2500, a command of {E1000} will cause the motor to
run 1000 steps clockwise to end at position 3500.
F - GO TO ABSOLUTE POSITION WITH INPUTS 1 & 2 AS STOPS
Syntax {Fxxxxxx}
This command is the same as the "D" command except that the two input pins are
monitored. If either of them is pulled low during the move, the motor will be decelerated
to a stop at the rate defined in the RAMP command (B). The position register will reflect
the current position when the motor has stopped. These inputs are level sensitive so if a
“F” command is used when one of the inputs is low, the motor will stop immediately.
Note: Allowing the motor to continue to running past a stop indicator is done for two
reasons; This method allows the motor to provide maximum braking torque during
deceleration and the position register integrity is maintained.
Step Coil A Coil B Coil C Coil D
1 ON
Off Off Off
2 ON ON
Off Off
3
Off
ON
Off Off
4
Off
ON ON
Off
5
Off Off
ON
Off
6
Off Off
ON ON
7
Off Off Off
ON
8 ON
Off Off
ON
