HX711 Load Cell Amplifier

Hey guys, I am trying to hook up my HX711 Load Cell Amplifier to a torque sensor that uses strain gauge technology. The recommended (calibration test excitation) voltage is 10VDC for the torque sensor, however I am not too sure how to supply 10VDC to the excitation wires if they have to be plugged into the HX711. Can i supply the 10v to the VDD & VCC voltage ? I’ve read multiple posts saying NOT to do this because it will fry the HX711 amp so I am not too sure what to do.

One idea I have is to wire the torque sensor (+) and (-) excitation wires to a breadboard first and supply power in that same row, then use another set of wires in order to lead into the HX711. Again, not 100% sure if this is safe so any help would be appreciated !

I have attached the specs of each part below. Thanks again !

HX711.jpg

Torque Sensor (tff350).pdf (234 KB)

It looks like just a strain gage bridge sensor. You can use 5V for the excitation voltage. The output will still be 2mV/V.

Parraback:
Can i supply the 10v to the VDD & VCC voltage ? I’ve read multiple posts saying NOT to do this because it will fry the HX711 amp so I am not too sure what to do.

In general, the fastest and best place to go for the answer to questions like that is…the datasheet for the HX711. There’s no need to go searching the internet for “posts” about the maximum voltage limit for that device. And you don’t have to understand the entire datasheet to find the maximum voltage. Anyway, the answer is: NO. Ten volts far exceeds the maximum voltage listed in the datasheet.

Parraback:
One idea I have is to wire the torque sensor (+) and (-) excitation wires to a breadboard first and supply power in that same row, then use another set of wires in order to lead into the HX711.

This sentence is ambiguous. It sounds like you might be planning to power the sensor with ten volts and the HX711 with five volts. Powering the sensor with ten volts would violate another of the HX711’s limitations (common mode voltage), so don’t. BTW, that’s a limitation that would not jump out at a beginner, so in that case, scouring the internet WAS a good idea.

Forget about ten volts and just hook the sensor up to the HX711 as if were a normal load cell (which, in essence, it is).

The HX711 excitation voltage is about 4.3 volts, so at full scale, the input to the HX711 will be about 8.6 mV (<-- 4.3 v x 2mV/V)…about half of the maximum permissible differential input voltage at the default 128 gain, so you won’t be using the HX711’s full capability. Nothing to be done about that, AFAIK.