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I have an Arduino project which requires reading pressure data from a pipe. The best pressure transducer I have been able to find is this one.

Seeing as though its max pressure is 150/200 PSI, will lower readings still be accurate, such as 30 PSI?

Thank you.

closed as off-topic by Juraj, Greenonline, sempaiscuba, VE7JRO, gre_gor Oct 24 '18 at 17:02

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Did you look further down the ad? This part seems important:

Pressure Range: 0-150 psi

Material :Stainless steel

Output: 0.5V – 4.5V linear voltage output. 0 psi outputs 0.5V, 75 psi outputs 2.5V, 150 psi outputs 4.5V

Working Temperature: -40—+125ºC;.

Works for oil, fuel, water or air pressure. Can be used in oil tank, gas tank, etc.

Accuracy: ±1%FS;

Thread: 1/8”-27 NPT. Overload Capacity: 2 times;

Pressure Medium: The gas and liquid which is compatible with 316L stainless steel;

Load Resistance: ≤(supply power-6.5V/0.02A)Ω; Long-term stability: ± 0.2%FS/year;

Temperature Effect on Zero: Typical: ±0.02%FS/ºC; Maximum: ±0.05%FS/ºC;

Temperature Effect on Sensitivity: Typical: ±0.02%FS/ºC; Maximum: ±0.05%FS/ºC;

Shock Resistance: 100g; Anti-Shock: ≤±0.01%FS(X,Y,Z axes, 200Hz/g);

Response Time: ≤1ms; Insulation Resistance: >100mΩ 500VDC;

Explosion-proof Class: ExiaTTCT6; Electromagnetism Compatibility: EN50081-1; EN50082-2; IEC61000-4-3;

Wiring connector: water sealed quick disconnect. Mating connector and wire harness (pigtail) is included. Wiring: Red for IN+. Black for GND. Green for OUT.

It tells you the accuracy over the range and even gives numbers for the effect of temperature on accuracy. It says it is linear. That means it measures the same at low values as it does at high values.

  • Accuracy: ±1%FS; .... that is ±1.5 psi .... it means that the accuracy is better at the top of the range than it is at the bottom of the range – jsotola Oct 24 '18 at 0:48
  • Wouldn't it be the opposite. 1% of a smaller number is a smaller error than 1% of a larger number. – Delta_G Oct 24 '18 at 1:01
  • Oh, 1.5% of full scale. So 1.5 psi no matter what. Which is a smaller percent error of a larger reading. – Delta_G Oct 24 '18 at 1:02
  • one thing that is missing from the spec sheet is repeatability .... it may be that a 30psi reading will always have a voltage reading that varies less than the 1.5 psi .... if that is the case, then you could calibrate the sensor by mapping the voltage reading to an actual psi reading in 1 psi steps and interpolate between the steps instead of interpolating between 0 psi and 75 psi – jsotola Oct 24 '18 at 1:15
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    Yes, it is going to give you plus or minus 1.5psi across the entire scale. – Delta_G Oct 24 '18 at 4:37
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This depends on your application.

This sensor shall read your 30 psi as 28 to 32 psi... Is it ok for your application?

As a rule of thumb a sensor which works at the 10/15% of its full scale is not the right choice.

Anyway, as I said, it depends on the application. If you need to detect if the pressure is below or above 15 psi it is ok, if you require to measure it to calculate something in a closed loop control, it could be hardly justified to use this.

Hope this helps.

  • Thanks. I just need to detect if the pressure is at a certain PSI, and if so, open a solenoid valve. I don't think a one to two PSI accuracy will be too bad. Do you agree? – Jamie Corkhill Oct 24 '18 at 13:56
  • Nobody here can agree or not whether or not 2 psi difference is too big or not because we don't know what you're building. For some things 2 psi is huge. For other things it's nothing. But right now you're the only one with the information to know what it is for your project. – Delta_G Oct 24 '18 at 15:34
  • @Delta_G You are right. I just want to open a solenoid valve to release pressure from a pool tank. I don't believe a 2 PSI delta will be too much of a problem. Normally, the pool tanks have an analog PSI gauge with a manual release, so I'm replacing the analog gauge with a transducer, and the manual lever with a solenoid. – Jamie Corkhill Oct 25 '18 at 20:22

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