Maximum value of ADCIN

[fratello]

I use this code :

    vmax = 0
    for cnt =1 to 70       			
        adcin 3, v_cal
        vmax =vmax max v_cal
        pause 100
    next cnt

    v_cal=vmax * 5000            ' I use VDD as Vref
    v_cal=div32 1023

write 0, v_cal.LowByte
pause 10
write 1, v_cal.HighByte
pause 10

[Darrel Taylor]

Then you have saved the value as a Voltage.
And 117 means 117mV.

Since I = E / R ... with a 0.02 ohm resistor ...

0.117 / 0.02 = 5.85 Amps

Dividing by 0.02 is the same as multiplying times 50.

117 * 50 = 5850 or 5.850 Amps.

[fratello]

One truck with e-beer for Mr.Darrel ! With thanks for fratello !
Now another worm walk to my convolutions ! If at start of colecting samples, my motor give me one peek (or "n" peeks) of voltage , but the real v_cal ( from the end of route) it's smaller than peek(s) , it's possible to reject them ? Something like here : http://www.picbasic.co.uk/forum/showthread.php?t=12183
It's possible to use :

AvgCount	CON  70		' Number of samples to average
FAspread	CON  50 	' Fast Average threshold +/-
Reject          CON  2          ' Spurious Rejection level
...etc - see post

[fratello]

Since the whole code don't fit into 12F675, I give up...till hw upgrade...
So, I put in my code one little delay (pause 500) before starting ADC reading...I hope it's enough.

[fratello]

It's ok with "pause'... I have though just one question...
If I use this code:

DEFINE OSC  4
DEFINE ADC_BITS 10
DEFINE ADC_CLOCK 3
DEFINE ADC_SAMPLEUS 50

....

 for cnt = 1 to 3
 	adcin 3, adval
 	vt=adval * 5000
 	vt=div32 1023
 	grup=vt+grup
 	pause 20
 next cnt
 vs=grup / 3

how small can be "pause' for correct reading of ADC ?
Thanks in advance !

[mackrackit]

It can be zero.

[Darrel Taylor]

You will still get correct A/D readings without any pause at all in there.

I guess it depends on how much the signal is changing, as to whether the average will be accurate or not.