HX711 only reads once on startup about hx711

[banoz]

Did you try to call scale.power_up() after scale.begin()?

[fenixil]

@Xarbenence
I hit the same issue today, so let me explain what's likely causing yours.
First, here is the link to the datasheet - https://www.digikey.com/htmldatasheets/production/1836471/0/0/1/hx711.html
As you can see, module can provide 10 or 80 samples per second. It needs some time to provide the value after it's started, that's why your first loop always succeeds as you wait for 1 second between iterations.
Your second loop does not have any delays, so it will exit almost immediately. You must add a delay there too.

weight = scale.get_units(); 
// ^^^^ you read the data here, so is_ready() becomes false
...
while(i<9){
if(scale.is_ready()){ // this is_ready() always fails
  long reading = scale.read();
  Serial.print("HX711 reading: ");
  Serial.println(reading);
  break;
} else {
  delay(100);
  // ^^^^ here
}

As I can see from the sources, begin() does not perform communication with the module, so it's not something that helps you here, but rather the delay at the end of the script, or something else.

I had and identical issue cause by power_up and power_down - I called power_up and expected data was available immediately. That was obviously wrong, so after I added some delay (just hardcoded 500ms to comply with Output settling time, however there are better APIs of achieving that, have a look at wait_ready_timeout and wait_ready_retry) everything got back to normal.

PS. I'd greatly appreciate if you edit your post, use github's markdown to make it look like a code and clean it up from commented code.