hello,

I have a 0-2 bar (0-30 psi) absolute pressure transmitter. It has 4-20 mA output. I set its lrv 0 mbar and urv 2000 mbar. At the workshop(bench) conditions i read about 4 mA? Is it true?

I thinks it was a gauge transmitter, and i set it again lrv: 0 mbar, urv: 2000 mbar, at the bench i should read 4 mA again?

I am a bit confused about this.

 

I meant, if it was a gauge pressure at my second part of my question.

>I have a 0-2 bar (0-30 psi) absolute pressure transmitter.
>It has 4-20 mA output. I set its lrv 0 mbar and urv 2000
>mbar. At the workshop(bench) conditions i read about 4 mA?
>Is it true?

>I thinks it was a gauge transmitter, and i set it again lrv:
>0 mbar, urv: 2000 mbar, at the bench i should read 4 mA
>again?

 

The gauge pressure transmitter should read 4.0mA when it is open to atmosphere with the range cited: LRV = 0mbar, URV = 2000mbar.

A correctly functioning absolute pressure transmitter ranged 0-2000mbarA (absolute) should read about 12mA when open to atmosphere, because 1 atmosphere is approx 1 barA (absolute) which is about half of the 0-2barA range.

Your absolute pressure transmitter is incorrect when it reports 4mA on the bench, open to atmosphere.

I suspect that someone has tried to 'calibrate' the absolute pressure transmitter without having a hard vacuum applied to the pressure port, where the pressure port was open to atmosphere. So the results of the 'calibration' are that it reports 'zero' pressure as a pressure close to atmospheric pressure, because that's the result of its 'calibration'.

It pays to check the model number stamped on the stainless steel ID tag to make sure it's an absolute pressure transmitter.

 

Thanks, David_2.

it is a 2090pa series transmitter.

With a vacuum pump, we could make 0,2 bara.
Then, with hart we defined this pleasure as 4 ma bu zero trim. Ä°t worked good.

When pt is open to atmosphere, if I make zero trim, and set lrv -1000, urv 1000 mbar; it gives 12 ma at atmosphere conditions. Is it a true way to calibrate it?