05-17-2022 10:18 AM
Hey guys I'm working on this LabVIEW Arduino interface project I'm trying to measure the pressure of a pump(max pressure of the pump is 70kpa) using an mpx5700dp sensor .. my problem is I need to convert the voltage into pressure and display it on the
waveform using this transfer function .... can someone help me undertand it pls
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05-17-2022 10:23 AM - edited 05-17-2022 10:25 AM
Well, it's a simple linear formula (until it falls apart at high pressures), so all you need is implement the math given in the picture using three diagram constants (slope, offset, excitation voltage). What have you tried?
05-17-2022 10:31 AM
the problem is I didn't understand it I made the interface but I didn't know how to get the slope the excitation voltage and the offset the maximum pressure of the pump is 70kpa
05-17-2022 10:40 AM - edited 05-17-2022 10:54 AM
Just change the constants to the values from the picture. Zeroes are not useful.
Of course you need to solve the formula for P(Vout), given the constants.
05-17-2022 10:46 AM
the offset voltage is 0 because it is linear but the sensitivity I didn't get is what I'm supposed to put
05-17-2022 10:50 AM - edited 05-17-2022 10:51 AM
@ihebz1 wrote:
the offset voltage is 0 because it is linear but the sensitivity I didn't get is what I'm supposed to put
That sentence makes no sense in so many ways! Did you look at my picture?
Also note that you don't need the separate pressure indicator if you show the digital display of the chart. We can typically offer much more specific help if you would attach your VI
05-17-2022 10:54 AM
@ihebz1 wrote:
the offset voltage is 0 because it is linear but the sensitivity I didn't get is what I'm supposed to put
Read the transfer function straight from the data you already gave (ignore the "error" part):
Vout = Vs*(0.0012858*P+0.04)
So solve for P (basic algebra):
P = ((Vout/Vs) - 0.04) / 0.0012858 = ((Vout/Vs)-0.04)*777.726 = 777.726*Vout/Vs - 31.109
So your gain is: 777.726/Vs
and your offset is: -31.109
05-17-2022 11:11 AM
from where the 777.726 came from ,, also -31.109
05-17-2022 11:52 AM
05-17-2022 12:00 PM