Need help with stepper motor program

Keith Vand

I wrote a rather lengthy program to control my senior design project, but the stepper motor part of it is causing a problem.· I need the stepper motor to rotate 132 times, that is 26,400 steps.· When the program gets to that part of the program the stepper motor rotates maye 10-20 times and then the whole program restarts.· This is the part of the program giving problems.

Rotate_Vert:
DEBUG "Rotating to Vertical: "
· Steps=26400
· DEBUG DEC Steps
· DEBUG " "
· OUTA=$1
· PAUSE 007
· DO
··· OUTA=$2
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$4
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$8
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$1
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
· LOOP
· PAUSE 1000
· OUTA=$0
· Status=1····· 'Position is remembered
DEBUG "Now in Vertical Position - "

Does anyone know why this would happen?· I have rewritten the program a few different ways and the result is always the same.

Post Edited (Keith Vand) : 4/5/2008 7:23:18 PM GMT

phil kenny

Attach your entire program and perhaps you will get help.

The problem may be in how you have declared the variables.

phil

Keith Vand

Ok, this is the whole program, and I attached a image file of the schematic of my circuit if that helps.


' {$STAMP BS2}
' {$PBASIC 2.5}
DIR0=1
DIR1=1
DIR2=1
DIR3=1
DIR15=1
Time VAR Nib
Cycles VAR Nib
Status VAR Bit
Steps VAR Word
Cycles=0
Status=0
FOR Cycles = 1 TO 15
· IF (Status=0) THEN GOSUB Move
· IF (Status=0) THEN GOSUB Rotate_Vert
· IF (Status=1) THEN GOSUB Dive
· IF (Status=1) THEN GOSUB Rotate_Hor
· DEBUG "End of Cycle "
· DEBUG DEC Cycles
· DEBUG " - "
NEXT
Hold:
GOTO Hold
Move:
DEBUG "Move Sequence: "
OUT15=1
Time=15
DO WHILE (IN13=0)
· DEBUG DEC Time
· DEBUG " "
· PAUSE 1000
· Time=Time-1
· IF (Time=0) THEN EXIT
LOOP
OUT15=0
DEBUG "End of Move Sequence - "
RETURN

Rotate_Vert:
DEBUG "Rotating to Vertical: "
· Steps=264000
· DEBUG DEC Steps
· DEBUG " "
· OUTA=$1
· PAUSE 007
· DO
··· OUTA=$2
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$4
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$8
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$1
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
· LOOP
· PAUSE 1000
· OUTA=$0
· Status=1····· 'Position is remembered
DEBUG "Now in Vertical Position - "
RETURN
Dive:
DEBUG "Dive Sequence: "
OUT15=1
DO WHILE (IN14=0)
· PAUSE 1000
· DEBUG "Diving... "
LOOP
OUT15=0
DEBUG "End of Dive Sequence - "
RETURN
Rotate_Hor:
DEBUG" Rotating to Horizontal: "
· Steps=264000
· DEBUG DEC Steps
· DEBUG " "
· OUTA=$1
· PAUSE 007
· DO
··· OUTA=$8
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$4
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$2
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
··· OUTA=$1
··· PAUSE 007
··· Steps=Steps-1
··· IF (Steps=0) THEN EXIT
··· DEBUG DEC Steps
··· DEBUG " "
· LOOP
· PAUSE 1000
· OUTA=$0
· Status=0······· 'Position is remembered
DEBUG "Now in Horizontal Position - "
RETURN

Keith Vand

I just found out that the program works exactly as intended when I disconnect the motor.· How could the motor cause the stamp to reset? Do I need to put a resistor or diode inbetween the stamp and the high power transisters?

phil kenny

Base resistors between the Stamp output pins and the transistors
driving the motor are needed to limit the current from the Stamp.

From the Basic Stamp FAQ:

On the BASIC Stamp I and BASIC Stamp II, each I/O pin is capable of
sourcing 20 mA and sinking 25 mA. The total across all I/O pins should
not exceed 40 mA source or 50 mA sink at any given time, however.

One exception to this rule exists with the BS2-IC. If the BS2-IC is powered
by an external 5-volt regulator capable of delivering at least 100 mA, the
total across each group of 8 I/O pins (0 - 7 and 8 - 15) can reach 40 mA source
or 50 mA sink providing a total of 80 mA source or 100 mA sink overall

In addition, it may be a power supply issue.

Try running the Stamp from a separate source.

phil

Post Edited (phil kenny) : 4/5/2008 10:23:36 PM GMT