8 Little Step-U
register is updated with each step. The {S} command will turn the motor windings on,
regardless of the value set by the {P} command.
Example: During the commissioning phase of a machine, the operator wishes to move to
a target position one step at a time using a pushbutton. The {S} command is sent and
the microcontroller is used to debounce each button press and apply a single pulse.
When the desired destination is reached, the position is read using the {U} command.
T - RETURN FROM REMOTE MODE
Syntax {T}
When the Little Step-U is operating in the REMOTE mode, sending a {T} will return to the
standard operating mode. The position register contents are valid and the motor windings
will be powered on or off according to the value previously set by the {P} command.
Example: Once the setup phase described above has been completed, a {T} command
readies the controller for full speed operation.
U - SHOW CURRENT STATUS
Syntax {U}
Returns [aaaa,bbbb,ccc]
The {U} command instructs the Little Step-U to send the current values of the Position,
Speed and Ramp registers back to the controller. The data consists of enclosing square
brackets ("[" and "]") containing the three (decimal) values separated by commas.
Example: A stepper is being used to move a print head mechanism. In order to
determine the paper width the user has selected, the motor is moved to one stop and
zeroed and then moved slowly to the other stop with RAMP set to 0. When the motor
stops (BUSY goes low), the position is retrieved with the {U} command. The controller
can then use this value to scale the print head movement commands and ensure that an
image will fit on the page.
V - SHOW STATE OF INPUT PINS
Syntax {V}
Returns [a,b]
The {V} command returns the current state of the two input pins in the form of "0" for a
low input and "1" for a high.
Example: An {G-1000} command is issued which instructs the Little Step-U to move
1000 steps counter-clockwise from the current position and to stop if it encounters a low
input on either IP1 or IP2. Checking that the complete move was made successfully is
made easier by only having to check two single digits with the {V} command, than
subtracting the current position from the earlier position and checking the result.
Multi-parameter commands
Movement related commands have the option of including speed, ramp time and/or step mode
values in the form of {X,speed,ramp,mode} where X is the command listed below and speed,
ramp and mode are valid values as described for the A, B and C commands above. Each
parameter is separated by a comma and may either be a value or no value (without spaces) if
that parameter is to remain unchanged. Any setting changed by using a command in this form
will remain at the new value for any subsequent commands unless explicitly changed.
D GO TO ABSOLUTE POSITION
E GO TO RELATIVE POSITION
