Analog output from Wheatstone Amplifier (Onl-38) using Phi-118 Loadcells

Help & Support
1

Hi!

I require your help regarding a problem I’m encountering.

Connecting 2 Phi-118 load cells to the Onl-38 Wheatstone amplifier. I am interfacing with a Campbell Scientific DataLogger. I need datasheets/wiring diagrams please.

Thank you so much in advance for your help!

2

Hi,

The Load Cell Shield is intended to work directly with an Arduino Board and provides a 0-3.3V analog output signal inherently (could be changed to 0-5V). Please be sure that your datalogger can take an analog signal to use the shield. Otherwise, you can use the HX711 Load Cell Amplifier which has an on-board ADC and provides a digital signal output.
If the shield can be used with your datalogger, you will find all the information/sample code/wiring diagram in these tutorials :




You can also consult the User Manual here

Hope this helps,

3

Thank you for your reply.

I am not using an Arduino Board. I am using a Campbell Scientific Datalogger. It can 0-5V or 0-3.3v inputs. Looking at the Wheatstone Shield, there are 2 inputs for the load cells. But there is no other information on the board. Is there an info on the board to describe what the inputs are, what the outputs are, and what are the power requirements for the board?

Charles Hahn

4

As mentioned in our previous reply, the information for the Load Cell Shield are available in its User Manual.

  • The LED of the load cell shield is powered through the 5V pin
  • A 3.3V on the 3.3V pin will power the load cells connected to Strain 1 and Strain 2 connectors on the load cell shield
  • The amplified analog output of the load cell connected on Strain 1 will be on A0 pin
  • The amplified analog output of the load cell connected on Strain 2 will be on A1 pin
  • Each channel has a gain resistor (default gain resistor is 100 Ohm for a gain of 495) that can be changed to change the gain of the amplifier according to this formula : Rgain= 49400/(Gain-1)
  • A trimpot is available for each channel to set the amplifier’s reference voltage to offset the output signal to a mid-supply