Vernier Digital Control User Manual
Page 6
11
In order to use the Digital Express VI, your stepper motor must be wired to the first
four output lines on the DCU. To drive a stepper motor, the Express VI sends a
pattern of on/off signals to the DCU to activate the electromagnets inside the motor
(“5,9,10,6” for clockwise and “6,10,9,5” for counterclockwise). This default pattern
sequence will work with many stepper motors; however, it can be adjusted if
necessary to match your manufacturer’s documentation.
Within the configuration window you have the option to set the total Number of
Steps, the Step Speed, and the Direction, or to create front-panel controls for these
parameters. Notice that the Step Speed is actually a time measurement specifying
how long a motor will wait before making the next turn step; therefore, a lower
number will result in a faster turn speed. For continuous movement, the Digital
Express VI should be placed inside a loop.
Figure 12 LabVIEW VI to control a stepper motor
LabVIEW Example Programs
We have included a nice set of example VIs with our LabVIEW files. You will find
these in the LabVIEW\examples\Vernier directory. Selected examples from this
directory are shown in Table 4.
Table 4
Name Description
DCUCAR
Allows forward and reverse keypad control of two DC motors.
DCUCOUNT
Input DCU pattern from 0–15 to turn on all DCU output patterns.
DCUSTEP
Control a stepper motor.
DCUSTEP3
Advanced control of a stepper motor.
DCUSUN
Use two light sensors and a DC motor to follow the direction of
a light source.
DCUTEMPC
Control temperature with a heater and fan.
DCUTOGGLE
Toggle DCU lines with the keypad.
DCUWARNV
Turn on a buzzer when a sensor reading is above a threshold.
Additional LabVIEW Resources
We have developed two books that introduce LabVIEW programming and provide
some great projects. The Hands-On Introduction to NI LabVIEW with Vernier lab
book (order code: LWV) introduces NI LabVIEW programming through a series of
hands-on exercises using a temperature sensor and microphone.
The Engineering Projects with NI LabVIEW and Vernier lab book (order code EPV)
contains twelve projects that introduce engineering concepts and LabVIEW
programming. This includes ten DCU projects complete with wiring diagrams,
materials lists, and challenge activities.
12
Warranty
Vernier warrants this product to be free from defects in materials and workmanship
for a period of five years from the date of shipment to the customer. This warranty
does not cover damage to the product caused by abuse or improper use.
Vernier Software & Technology
13979 S. W. Millikan Way
Beaverton, OR 97005-2886
Toll Free (888) 837-6437
(503) 277-2299 FAX (503) 277-2440
www.vernier.com
Rev. 12/2/2013
Logger Pro, Logger Lite, Vernier LabQuest, Vernier LabQuest 2,Vernier LabQuest Mini, Vernier LabPro, Go!
Link,
Vernier EasyLink and other marks shown are our trademarks or registered trademarks in the United States.
National Instruments, NI, ni.com, and LabVIEW are trademarks of National Instruments Corporation.
TI-Nspire, CBL 2 and CBL, TI-GRAPH LINK, and TI Connect are trademarks of Texas Instruments.
All other marks not owned by us that appear herein are the property of their respective owners, who may or may not be
affiliated with, connected to, or sponsored by us.
Printed on recycled paper.