The accuracy of the pressure sensor is 0.25%FS. What does FS mean?

01Accuracy of pressure sensors in the WIKA sample
In the WIKA catalog, the accuracy of the pressure transmitter is marked as follows:
Yesterday a student asked, what does the suffix FS mean for 0.125%FS?
Let’s talk about this issue today.
02The meaning of full scale accuracy and reading accuracy
Reading accuracy: It is the error proportional to the measured value.
Full Scale Accuracy: It is an error proportional to the range. It is a fixed error representation method. It is an error relative to the full scale of the instrument and is expressed as a percentage.
The FS in the WIKA catalog is Full Scale!
03Calculation Example
In stress testing, we often use full-scale accuracy.
Suppose we have two pressure transmitters, both have a measuring range of 100 bar.
Let’s take a look at the difference between the error values ​​calculated using reading accuracy and full-scale accuracy.
(1) Reading accuracy ±1%
The system pressure value is 10bar: the measurement error is ±0.1bar;
The system pressure value is 50bar: the measurement error is ±0.5bar;
The system pressure value is 100bar: the measurement error is ±1bar;
(2) Full scale accuracy ±1%
The system pressure value is 10bar: the measurement error is ±1bar;
The system pressure value is 50bar: the measurement error is ±1bar;
The system pressure value is 100bar: the measurement error is ±1bar;
I believe that after comparing the two, you can see that if the product you choose uses reading accuracy to express the accuracy level of the product in the sample, then under the condition of the same accuracy value, the pressure transmitter expressed by reading accuracy is definitely more accurate than the pressure transmitter marked with full-scale accuracy.
Then wouldn’t it be better if we all buy pressure transmitters that are expressed in reading accuracy in the future?
But the reality is cruel…
04Is there a pressure transmitter that is expressed in terms of reading accuracy?
The answer is yes!
However, it should be noted that no pressure transmitter can always maintain the same accuracy over the entire range.
Therefore, even if the pressure transmitter you choose is indicated by reading accuracy, it also has a certain range limitation.
Take the 100bar pressure transmitter as an example. Its sample is marked as 0.01% RD (reading accuracy), but the reading accuracy corresponds to the range of 10% to 100%, that is, from 1MPa to 10MPa. The accuracy of the range from 0 to 1MPa needs to be given separately.
How expensive is it?
I once bought a pressure transmitter, and its parameters were marked like this:
It specifies two precisions and then says to take the larger value.
Please guess how much this pressure sensor costs. Please leave a comment in the comment section! Please use your imagination…