jremington:
The HX711 is a digital device. You don't read the output of the HX711 using the analog inputs, so remove the connection to A0.It looks like you have mixed in some PID code intended for a completely different type of sensor.
Make sure that the HX711 and load cell is working correctly, and that you understand the output, before trying anything else.
Sparkfun has a clear guide describing how to connect the HX711 to Arduino.
If you want to use the values produced by the HX711 as input for some PID controller, that is fine. However, those input values would be internal to the program, not the hardware.
Hi, thank you for the reply.
I do understand that the HX711 is a digital device and I did actually use that guide! Our load cell and HX711 amplifier are working well and calibrated in gram-force down to 2 decimals.
And I tenuously understand how using PID code for analog input with a digital device would not work. I had been told by someone with more experience than me that this would work, and I had thought that the Arduino could convert those digital values into something readable in analog. (Very novice here).
Using the values produced by the HX711 for the PID was an option I had in mind.
i.e. Mapping the range of tension we see and using that as the PID input.
Do you know if it possible for me to use some digital to analog converter and continue as it is setup?
Wawa:
Why is the VDD pin of the HX711 connected to 3.3volt.
That's if you use a 3.3volt Arduino.A Mega is a 5volt Arduino, so both VCC and VDD go to the 5volt pin.
It shouldn't make a difference, but VDD to 5volt could make data more reliable.
Leo..
I had just begun thinking about this the other day. I brainlessly followed the guide in this fashion without thinking about the fact that the board has a 5V logic level. I do not even think I have tried both VCC and VDD on the 5V pin.
I will try this, thank you!