Step motor control

[aratti]

You can improve your motor performance in two ways:

1) Use half step sequence ( here a sample code)

HStep           var byte    [8]     ' Half step sequence array
B0              var byte
C0              var byte
P0              var byte
W0              var word

TRISB = 0


P0 = 50   ' incrementing the delay will reduce the motor speed  (max 255)
C0 = 0
B0 = 0

HalfMode:                      
If C0 = 0 then gosub CW
C0 = C0 + 1
if C0 = 2 then C0 = 0
If C0 = 0 then gosub CW
If C0 = 1 then gosub CCW

for W0 = 0 to 8192   ' one turn of the gear shaft ( 64 motor turns)
PortB = HStep[B0]
B0 = B0+1   
if B0 = 8 then B0=0
pause P0
next W0

Goto HalfMode

CW:        ' half step sequence (clockwise)
HStep[0] = 1
HStep[1] = 3
HStep[2] = 2
HStep[3] = 6
HStep[4] = 4
HStep[5] = 12
HStep[6] = 8
HStep[7] = 9
return

CCW:       ' half step sequence (counter clockwise)
HStep[0] = 9
HStep[1] = 8
HStep[2] = 12
HStep[3] = 4
HStep[4] = 6
HStep[5] = 2
HStep[6] = 3
HStep[7] = 1
return

end

2) Use a constant current setup to your motor. The simple way is to use a LM317 configured as costant current supply. See the attached schematic (Resistor 33 Ohms 1 watt. Use 24 V dc as an input to the LM317)

cheers

Al.