hi martin
ive looked at my breadboard and found I had the wrong pull up resistor as id been experimenting, with the original 267R fitted im getting similar results but ive noticed my bread board is terrible, slightest move of a jumper wire and readings are erratic, I will need to invest in a better quality one, I have alo found my original resistance test formula is marginally more accurate across a wider range than using the FVR equivalent, one issue I have noticed is when removing the resistor under test the display does not drop back to 0 ohms, if I removed just the pull up resistor it does, so the adc input needs to be held low to do this is there any way round where by removing the test resistor I get the display to drop to 0 ohms ?
cheers bob
Using FVR on a adc channel
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siliconchip
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medelec35
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Re: Using FVR on a adc channel
Hi Bob.
Think of a DMM.
With no resistance connected it won't show 0R as that is a short circuit, i.e very low value resistance.
With no test resistor present, but hardware should be OL (Over Limit).
What I would do with not test resistor then note ADC or result value.
Add a decision branch on under the values to show OL or 9999 etc.
As for FVR, I Don't recommend it being used in this case.
Think of a DMM.
With no resistance connected it won't show 0R as that is a short circuit, i.e very low value resistance.
With no test resistor present, but hardware should be OL (Over Limit).
What I would do with not test resistor then note ADC or result value.
Add a decision branch on under the values to show OL or 9999 etc.
As for FVR, I Don't recommend it being used in this case.
Martin
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chipfryer27
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Re: Using FVR on a adc channel
Hi
You mentioned issues with your breadboard but personally I have found far, far more issues with jumpers.
Many you get "free" are a complete liability as the quality is non existent. The pins are close, but not exactly the dimensions to ensure reliable connection.
A couple of years ago I went through my collection and binned any that failed a test. I think I posted the chart I used to test the jumpers (m2m / m2f / f2f).
Regards
You mentioned issues with your breadboard but personally I have found far, far more issues with jumpers.
Many you get "free" are a complete liability as the quality is non existent. The pins are close, but not exactly the dimensions to ensure reliable connection.
A couple of years ago I went through my collection and binned any that failed a test. I think I posted the chart I used to test the jumpers (m2m / m2f / f2f).
Regards