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Participant

Join Date: May 2010
Posts: 2

Zero A Capillary With a Meriam

05/20/2010 3:05 PM

I am trying to figure out how to zero a capillary x-mitter with my meriam 4100. I was able to adjust the zero trim, but I know that is not what I needed to do, I did it to help that vessel limp along for now. My range is -10.46 to -3.46. My zero was +7 when the flanged sensing elements were side by side.

Thanks

Dustin

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Commentator

Join Date: Dec 2007
Location: texas
Posts: 92
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#1

Re: Zero A Capillary With a Meriam

05/20/2010 11:29 PM

Hi,

If you are measuring level with a capillary D/P cell ranged from -10.46" of water to -3.46" of water these values will give you a span of 7" of water.

With the transmitter installed on the vessel and assuming that the High side of the transmitter is at the datum point (the point where you want to start measuring level) this is how I would check and/or correct the transmitter's zero.

1)Block in BOTH the low and the high legs of the transmitter

2)Vent BOTH legs to atmosphere and make sure that they are both clear(not plugged up)

3)Connect your meriam and check the transmitter's output and PV, you should have a PV of -10.46"of water, with an output of 4mA.

If the PV is not -10.46" then the transmitter's LRV needs to be changed to whatever the PV is showing on your meriam,the URV needs to be changed to as well (7" span)

After verifying that the PV is -10.46" and assuming that it was, then the ranges stayed unchanged(-10.46 to -3.46) the transmitter's output should be 4mA if is not, then do a "trim zero" with your meriam (is very unlikely that trim zero will be necessary).

4) If you want to check 100% level, apply 7" of water pressure to the high side of the transmitter the PV should go to -3.46" of water and the output of the transmitter should be 20mA.

I hope this helps...Thank you

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Participant

Join Date: May 2010
Posts: 2
#2

Re: Zero A Capillary With a Meriam

05/21/2010 2:23 PM

After I posted this I realized I accidently fixed it by doing what you have described here. I had it fixed for a few hours but thought I had messed it up and the other tech just sat there and let me think that I did not have it fixed yet when he knew I did

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