Hx711 calibration – 65 days old

[amod]

Iam using load cell amplifier HX711 module.I have got raw values from module but iam not able to calibrate with load cell.I want make a universal calibration factor in which I can use any type of load cell. Secondly I want to tare the values.pls help.

[ricardourio]

Hello,

No calibration is almost impossible, load cells works with very low signals so it's important to gage it. I suggest that you create a calibration routine, that you record no load value and a loaded value, like 1 Kg.

Ricardo Urio

[amod]

Pls guide me ,how I can get average of adc values.example needed.

[ricardourio]

Hello,

It's a very basic question, and you will need to make some research. A initial way is to create a routine where you read 12 times the adc value, recording the sum of all values and min and max, in the end you divide the sum by 10 after subtracting the min and max values. It's necessary to do it with no load and with a knowed load. After it the variation Kg/mv wil be defined.

Ricardo Urio

[John Drew]

Hello Amod
Another way is to bring in an odd number of samples into an array, sort the array and then use the middle value. I saw this elsewhere on the forum and it seems to work well although I think Ricardo's method is a good solution too.
In the past I have just sampled a number of times and calculated an average.
John

[amod]

I got the values in kg and they are stable.

I want to include TARE function to my project.When i minus current reading it gets zero but till i press button.When i Release button same old readings displays.
pls Help.

[SimonJA]

Hi Amod

I would do it something like this:

Use an adjustment variable, initially set to zero, when you press the button set the adjustment variable to the current averaged ADC value from the load cell.

For the output/display reading subtract the adjustment variable from the current averaged ADC output.

If you have trouble doing that post your code and I'm sure you'll get some help.

[amod]

my Program

Device = 16F877A
Xtal = 20
All_Digital On
Include "modedefs.bas"
Declare LCD_DTPin = PORTB.4
Declare LCD_RSPin = PORTB.2
Declare LCD_ENPin = PORTB.3
Declare LCD_Interface = 4
Declare LCD_Lines = 2
Declare LCD_Type = 0


Dim y As Dword
Dim i As Byte
Dim COUN As Dword
Dim gram As Float
Dim Value As Word
Symbol TARE = PORTC.3
Symbol ADDO = PORTC.4
Symbol ADSK = PORTC.5
TRISC=%00011000
DelayMS 150
Cls


Main:
ADDO=1
ADSK=0
COUN=0
While ADDO=1:Wend
For i= 0 To 23
ADSK=1
COUN=COUN<<1
ADSK=0
If ADDO =1 Then Inc COUN
Next i
ADSK=1
COUN=COUN^0x800000
gram=8388608-COUN
gram=((coun-124000)*10)/500
gram=gram-165090
y=0
If TARE=1 Then y=y-gram
ADSK=0

Print At 2,4, Dec1 y
GoTo Main

[SimonJA]

I think something like this should give you an idea:

If BUTTON1 = 0 Then 
adjustmentVal = gram
EndIf

displayVal = gram - adjustmentVal

You would not need to worry about debouncing the button, I assume your code is looped through quite quickly so as long catch the event it would set the value.

You would need to make the button an input on a pic port (to ground) and have a pull-up resistor or enable one in software.

[amod]

Thanks SimonJA.I got my work done.
My new problem is that my program runs fine on lcd but when i converted my code for 6 digit seven segment display all segment blinks for half a second repeatedly.
and it only show positive value and doesnt show negetive value.
here is my code


Device = 16F877A
Xtal = 16
Include "modedefs.bas"
All_Digital = True





Dim dg1 As Dword
Dim DG2 As Dword
Dim DG3 As Dword
Dim DG4 As Dword
Dim DG5 As Dword
Dim DG6 As Dword

Dim DIGIT As Dword
Dim DG As Byte
Dim COUNTT As Byte


Symbol TARE = PORTD.4
Symbol ADDO = PORTC.3
Symbol ADSK = PORTC.4



Dim N As Float
Dim adjval As Dword
Dim disval As Float
Dim i As Byte
Dim COUN As Dword
Dim gram As Float


TRISA=0
TRISC=%00001000
TRISB=0
TRISD=%00010000
TRISE=0

GoSub display


Main:
ADDO=1
ADSK=0
COUN=0
While ADDO=1:Wend
For i= 0 To 23
ADSK=1
COUN=COUN<<1
ADSK=0
If ADDO =1 Then Inc COUN
Next i
ADSK=1
COUN=COUN^0x800000
gram=8388608-COUN
gram=gram/50
ADSK=0
If TARE=0 Then 'tare routine
adjval=gram
EndIf
disval=gram-adjval
N=disval
GoSub display
GoSub DIGITCALC
GoTo Main


display:
For COUNTT=0 To 99

PORTB=dg1
PORTA.5=0
DelayUS 100
PORTA.5=1

PORTB=DG2
PORTA.4=0
DelayUS 100
PORTA.4=1

PORTB=DG3
PORTA.3=0
DelayUS 100
PORTA.3=1

PORTB=DG4
PORTA.2=0
DelayUS 100
PORTA.2=1

PORTB=DG5
PORTA.1=0
DelayUS 100
PORTA.1=1

PORTB=DG6
PORTE.0=0
DelayUS 100
PORTE.0=1

Next COUNTT

Return


DIGITCALC: ''THIS ROUTINE BREAKS UP THE NUMBER INTO 3 DISTINCT PARTS - DG1,DG2,DG3,DG4,DG5,DG6
'NOTICE THAT ANOTHER SUBROUTINE IS CALLED EACH TIME


DIGIT=0
LP1:
If N<10000 Then DS1
N=N-10000
DIGIT=DIGIT+1
GoTo LP1
DS1:
GoSub FND
dg1=DG
DIGIT=0
LP2:
If N<1000 Then DS2
N=N-1000
DIGIT=DIGIT+1
GoTo LP2
DS2:
GoSub FND
DG2=DG


DIGIT=0
LP3:
If N<100 Then DS3
N=N-100
DIGIT=DIGIT+1
GoTo LP3

DS3:
GoSub FND
DG3=DG


DIGIT=0
LP4:
If N<10 Then DS4
N=N-10
DIGIT=DIGIT+1
GoTo LP4

DS4:
GoSub FND
DG4=DG


DIGIT=N
GoSub FND
DG5=DG

Return




'_________________________________________________ _________________________


'_________________________________________________ _________________________
FND: ''THIS ROUTINE IDENTIFIES THE SEGMENTS TO LIGHT UP

'7 SEGMENTS WIRED UP AS FOLLOWS

'A -PORTB.7
'B -PORTB.6
'C -PORTB.5
'D -PORTB.4
'E -PORTB.3
'F -PORTB.1
'G -PORTB.2
'DECMAL=PORTB.0

FND0:
If DIGIT>0 Then FND1
DG=%00000101
GoTo FNDEND

FND1:
If DIGIT>1 Then FND2
DG=%10011111
GoTo FNDEND

FND2:
If DIGIT>2 Then FND3
DG=%00100011
GoTo FNDEND

FND3:
If DIGIT>3 Then FND4
DG=%00001011
GoTo FNDEND

FND4:
If DIGIT>4 Then FND5
DG=%10011001
GoTo FNDEND

FND5:
If DIGIT>5 Then FND6
DG=%01001001
GoTo FNDEND

FND6:
If DIGIT>6 Then FND7
DG=%01000001
GoTo FNDEND

FND7:
If DIGIT>7 Then FND8
DG=%00011111
GoTo FNDEND

FND8:
If DIGIT>8 Then FND9
DG=%00000001
GoTo FNDEND

FND9:
DG=%00011001

FNDEND:
Return
'______________________________