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Pressure Sensor for water level measurement

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Do you think that the drift seen must be due to atmospheric pressure change and not due to any problem with the sensor?
I have no way of knowing.
 
This "thing" is supposed to tell me but it looks like a rock on a string and it didn't come with any instructions.
One of these (except this one has instructions)?
Sensor.gif
 
Not like that. Why it is not working and can it be used.
I mean why the voltage output is not stable and whether this sensor can be used for my application. These are the questions for which I try to find answer. Not "we bought this, make it work". That is only your interpretation :D
 
One of these (except this one has instructions)?
View attachment 92162
I've been there a few times in the '70s when I worked for Bristol Aerospace launching Black Brandt Rockets.

I also experienced this while trying to drive back from the Research Range back into Churchill.

" If you can't see the rock in front of you in full daylight, it's a white-out"

My 1st design of a Doppler Tracking system with an ultra stable OCXO PLL subcarrier on telemetry worked for tracking rocket position from subcarrier drift with frequency> 1e-10

My last design failed after I left for a better job, but it worked in the lab. It was a HP9825 dual calc SCADA 200 channel A/D remote control system for ground control of Rockets. The problem they failed to solve was Short Wave interference with RS485 1km link. All it needed was a CM choke and RF caps.
 
See post #48.
I had the temperature sensor readings also .If you see any anomalies , I will arrange the readings again. The Air Conditioner in the room was intermittently switched ON and OFF. My work place is shifted and it may take some more time to fix this set up as the new place doesn't have sufficient height (due to false ceiling) to fix the pipe.:)
upload_2015-4-23_6-57-48.png
 
Prem, if you have this data in Excel, try plotting the values on a graph.
It looks quite interesting, I am not sure what it proves but I think it is interesting.

JimB
 
Prem, if you have this data in Excel, try plotting the values on a graph.
It looks quite interesting, I am not sure what it proves but I think it is interesting.

JimB
AS it turned out that only took me a few minutes Temperature Correlation is indeed useful for improving the accuracy.

upload_2015-4-23_1-25-9.png
 
There is obviously other sources of error below 1047, but above 1047, the correction factor is a linear relation.

i wish you could get a more accurate reference and analyze your errors.
 
AS I said before the reference is the Bandgap reference voltage in both DMM and ADC needs to be temperature stable. <<+-1 deg C

E.g. with some effort , you can make a 1V stable reference, then you could subtract this and measure in a lower scale and improve accuracy.
Then you could investigate RF effects by putting on a small RF cap and observe and many more things. This is getting repetitious.
 
AS I said before the reference is the Bandgap reference voltage in both DMM and ADC needs to be temperature stable. <<+-1 deg C

E.g. with some effort , you can make a 1V stable reference, then you could subtract this and measure in a lower scale and improve accuracy.
Then you could investigate RF effects by putting on a small RF cap and observe and many more things. This is getting repetitious.
As I mentioned before, my test set up is disturbed due to office shifting. Once it is set up, I will start my testing again. All the valuable suggestions I got through this forum will be tried out then.:)
 
Even without an office , you can order parts and get delivered make a 1V programmable zener reference with heater R and thermistor in a mini-over and operate at a fixed Temp just above ambient max. with styrafoam insulation, it can heat up in 15 seconds and be stable. We used this method for testing crystal temperature cooeficients to calibrate within 1ppm. Material cost was < 1 hr salary. Got a budget?
 
Now that I have had some sleep, here is my graph:

Water depth.JPG



The time of day is on the X axis.
The 50m PTX is the blue trace
The external PTX is the red trace
The temperature TX is the yukky green trace.

All values have been normallised to "per unit", of the values at 14:15.

JimB
 
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