how to get the maximum deviation %fs of press. transmitter

Hi there,

I am not sure what you are asking for?

If you want the maximum percentage full scale deviation of the transmitter and your transmitter is NAMUR compliant then full scale (overange) will be 22 mA. So you have 16mA to measure with so 2/16*100 = 12.5%

If you want this in psig then 105.1/16 = 6.57mA per PSIG = (2 * 6.57) + 101.5 = 114.64 psig @ 22mA

You will have to be a bit more specific with your question.

Regards,

Craig

Guru,

thanks, one more favor pls.?

they gave a sample form, i wondering how they get the maximum deviation of %FS As-found +/- 0.75 and as left +/- 0.13

Range input pressure: 0.00, 18.13, 50.75, 76.13, 101.50 respectively.

Rising O/P mA Actual: 4.0, 8.0, 12.0 16.0, 20.0

Rising measured as found: 4.09, 8.052, 12.075, 16.091, 20.120

Rising measured as left: 4.00 7.996 11.998 16.013 20.021

Rising Error mA as found: 0.059 0.052 0.075 0.091 0.120

Rising Error mA as left: 0.000 -0.004 -0.002 0.013 0.021

thanks,

raffy

Hi there,

The answer lies with the two points you mentioned:

Measured as found: 20.120 mA

Measured as left: 20.021 mA

As you are dealing with % Full scale error - 20 mA is full scale - so anything above this is your error.

As stated earlier - your measuring range is 4 - 20 mA, this gives you 16 mA to measure with.

As Found

So: 20.120 mA - 20 mA = 0.120 mA (the error)

0.120 mA / 16 mA * 100 = 0.75%

i.e. Error / Measuring range * 100 = % error on full scale

As Left

20.021 mA - 20 mA = 0.021 mA

0.021 mA / 16 mA * 100 = 0.13%

i.e. Error / Measuring range * 100 = % error on full scale.

This is especially important when your transmitters are used for custody of transfer and that sort of thing.

I hope this makes things a little bit clearer for you.

Regards,

Craig