DP transmitter negative readings

Instrumentation Flow
1

Hi, my DP transmitter Rosemount 3051 Coplanar type and impulse lines high and low connected wrong. due to wrong connection display indicate minus value. How can i change direction from field communicator menu trees. i cannot find this place.

Thanks, Rasim

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2

Hi,

First correct the HP and LP connections, then check the readings.

If not solved, do calibration again.

At last option, do factory reset if nothing works. Then again do calibration as per your application.

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3

Thanks for your response.
i do not want to correct the HP and LP connections, i want change reading from menu. (setting)

4

its not possible. you will not get correct readings.

With wrong connections, you are applying high pressure on LP side of DP transmitter, your sensor may damage.

is there any specific reason? to use the wrong connections?

5

You can change the range of the transmitter.

Apply different ranges which includes negative and positive values then check.

Note: Your instrument/sensor will fail soon with wrong connections. Measurement is not possible with wrong range, its only to get some +ve value on the instrument display.

I think you know what you are doing otherwise correct the installation.

6

While I don’t think it is the greatest of ideas and considering that it is a flow it may not be possible.

However, if you change your range from say 0-100 " H2O to -100 -0 " H2O you should be able to achieve the same mA out put to your control system therefore getting a correct reading. Essentially no different than using a wet leg on you LP side of a level.

Also I do not see why you would damage your diaphragm seeing how both sensors would be sitting in the same line pressure essentially. Then again I am not certain this would work just spit balling an idea.

The easiest fix would just be to fix the mistake and swap your impulse lines rather than doing a bunch of paper work and working on my theory.

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7

So while my little theory sounds and reads good. I do not think it would work lol. You may not be able to compensate the pressure drop across the orifice with the impulse lines reversed.

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8

You could isolate your transmitter and take the transmitter off of its mounting and flip just the transmitter.

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