Power supply for multiple devices -- effects on accuracy

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Discussion Overview

The discussion revolves around the potential effects of using a single regulated power supply for multiple devices in a project involving a Force vs Displacement graph. Participants explore concerns about accuracy in measurements from a potentiometer and a load cell when powered by the same supply.

Discussion Character

  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether the output values from the potentiometer and load cell will be affected by sharing the same power supply, particularly in terms of accuracy.
  • Another participant suggests that knowing the specifications of the power supply and the accuracy requirements of the setup is crucial for assessing potential issues.
  • It is proposed that using a reference input on the DAQ that samples the supply voltage could help improve accuracy by compensating for ripple and droop, though it won't address errors from the sensors or the DAQ itself.
  • A participant emphasizes the importance of connecting the ground (0v) of the power supply to the ground of the DAQ/microcontroller to ensure proper operation.
  • There is a caution about ensuring that the maximum voltage from the potentiometer and load cell does not exceed the maximum input voltage of the DAQ.
  • It is suggested that ideally, the DAQ/microcontroller should also be powered from the same supply as the other devices, possibly through a regulator.

Areas of Agreement / Disagreement

Participants express various concerns and suggestions regarding the setup, but there is no consensus on the extent of the impact of using a shared power supply on measurement accuracy.

Contextual Notes

Participants do not provide specific details about the power supply's specifications or the accuracy requirements of the setup, which may limit the discussion's depth regarding potential issues.

Who May Find This Useful

This discussion may be useful for individuals working on projects involving data acquisition systems, particularly those using multiple sensors powered by a single power supply.

belae1ka
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Hi,

For my project I am plotting a Force vs Displacement graph using 2 analog inputs which are going to a DAQ.

The two analog inputs are coming from;
-A 5k potentiometer (for the displacement)
-A 1000 lb load cell sensor (for the force)

I would like to use a regulated 12V DC (1Amp) power supply for both the potentiometer and the load cell. I would like my graph to be accurate.

I am curious as to if the output values from one device will be affected if another device is using the same power supply.

Do I have to worry about this potential issue if I am using a "regulated" power supply?

Here is a link to the power source I am using ;
https://www.amazon.com/gp/product/B00K93AYTK/?tag=pfamazon01-20

Here is the datasheet for the load cell;
http://keli-cee.pl/dokumenty/134_DEFY-SS Datasheet.pdf

Thank you.
 
Last edited by a moderator:
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Do you know the specs of the supply? Do you know the accuracy requirements for your setup? If you supply an input of your DAQ as a reference that is sampling supply voltage this should improve accuracy. This will tend to cancel ripple and droop but it will not make up for errors from the sensors themselves or the DAQ.
 
In case it's not obvious... You will also need to connect the 0v of power supply to the 0v of the DAQ/microcontroller.

You should ensure that the maximum voltage produced by the potentiometer and load cell can't exceed the max input voltage of the DAQ.

Ideally power the DAQ/microcontroller from the same power supply as the potentiometer and load cell (via a regulator if necessary).
 
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Thanks guys
 

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