Reading Analog input from AD620AN , output misbehaving on Serial monitor


I am using load cell(200kg) connected with AD620AN(load cell amplifier). I am getting proper output on of amplifile(checked by multi meter). When i am reading this value from arduino UNO analog pin(A0, A1). Serial monitor is giving some different data.

Please find screen shot of output.

also find the code i am using.

#include <XBee.h>
#include <SoftwareSerial.h>
SoftwareSerial mySerial(2, 3); // RX, TX
XBee xbee = XBee();

uint8_t payload = { 0, 0 };

// SH + SL Address of receiving XBee
XBeeAddress64 addr64 = XBeeAddress64(0x0013A200, 0x40DC8215);
ZBTxRequest zbTx = ZBTxRequest(addr64, payload, sizeof(payload));
ZBTxStatusResponse txStatus = ZBTxStatusResponse();

int offset1=0;
int offset2=0;
int L1,L2,L3 = 0; //
int statusLed = 13;
int errorLed = 13;

void flashLed(int pin, int times, int wait) {

for (int i = 0; i < times; i++) {
digitalWrite(pin, HIGH);
digitalWrite(pin, LOW);

if (i + 1 < times) {
void setup() {
pinMode(statusLed, OUTPUT);
pinMode(errorLed, OUTPUT);



void loop() {
// put your main code here, to run repeatedly:
String dataString;

dataString= String(L1)+","+String(L2)+";";
float weight = ((L1-offset1)+(L2-offset2))/2.3;

payload[0] = int(weight) >> 8 & 0xff;
payload[1] = int(weight) & 0xff;


// flash TX indicator
flashLed(statusLed, 1, 50);



I never seen anything above 19200 baud to work reliably on a SoftwareSerial but it's good to block the Arduino do the rest very badly (it blocks interrupts during sending and receiving and interrupts are necessary for a lot of things in the Arduino platform).

Test your stuff without SoftwareSerial and if everything works connect the XBee to the hardware serial interface.

Thanks for your replay,

My “AD620” IC (pin number 6 output with respect to ground of arduno) is constantly 90 mV without load on loadcell. when i am putting load on loadcell the output of AD620 is amplified to around 250 mV.

Please find the circuit diagram attached.

I am unable to understand why me serial monitor is showing this output.

I am unable to understand why me serial monitor is showing this output.

You still didn't tell us what output you get nor what you expect.