Microchip Technology PICDEM Mechatronics Demo Board DM163029 DM163029 User Manual
Product codes
DM163029
PICDEM
TM
Mechatronics Demo Board User’s Guide
DS51557C-page 34
©
2006 Microchip Technology Inc.
FIGURE 2-13:
PROJECT 6: SCHEMATIC
Instructions
POT1 adjusts the speed of the motor. Set POT1 at 100% to run the motor at full speed.
The speed indicated on the LCD should be similar to the speed shown in Project 5.
Next, run the motor at half speed by setting POT1 to 50% and do the comparison again.
The speed indicated on the LCD should be similar to the speed shown in Project 5.
Next, run the motor at half speed by setting POT1 to 50% and do the comparison again.
Discussion
Back EMF is typically not as accurate as speed feedback from an optical encoder.
However, in many applications the accuracy does not have to be very precise and
measuring Back EMF is more cost effective than any other speed feedback
mechanism.
However, in many applications the accuracy does not have to be very precise and
measuring Back EMF is more cost effective than any other speed feedback
mechanism.
PIC16F917
V
DD
AN0
V
SS
V
DD
1 k
Ω
R10
11/32
2
12/31
POT1
10 k
Ω
V
DD
C26
1000 pF
1000 pF
COM
X
SEG
X
Common pins
Segment pins
LCD1
VIM-332-DP
U11:B
U10:A
Motor
10 k
Ω
10 k
Ω
V
DD
Simplified circuit shows
equivalent functionality
AN4
1 k
Ω
R32
7
C36
1000 pF
1000 pF
Back EMF
Back EMF
RD7
30
CCP2
21
Note:
Different motors have different speed characteristics. The motor used at the
time this manual was written may be different from the motor shipped with
your PICDEM Mechatronics Demo Board. Verify that the motor data sheet
included on the CD-ROM matches the motor on the board. If they are
different, go to Microchip’s web site for updates to this project.
time this manual was written may be different from the motor shipped with
your PICDEM Mechatronics Demo Board. Verify that the motor data sheet
included on the CD-ROM matches the motor on the board. If they are
different, go to Microchip’s web site for updates to this project.