Flow Transmitter Values for Gas Turbine

A

Thread Starter

abdi

hi,

We have a flow transmitter when we check the setting of this transmitter with HARD system. I see these value for range values:

URL: 9.05 KG/S
LRL: 0 KG/S
USL: 2.9006 KG/S
LSL: 0 KG/S

I think URL & LRL are the range value and these range is corrected for flow and the USL & LSL are the sensor limit but I confused why the sensor limit is less than the range value. I know the range value from zero to 9.05 kg/s is correct.

The type of this flow meter is orifice. when connected to this transmitter by HARD system, we see the dp value, PT value, TT value & mA value. we have six this flow meter for six turbines. for each gas turbines this flow meter has correct dp, TT, PT value. but for one of these gas turbine the USL value is 0.60817, and when this flow meter calculate the flow, the flow value is 1/5 correct value. for example for gas turbine load the flow must be 6.5 kg/s, but the transmitter indicate 1.45 kg/s.

The flow value for another flow meters means for five turbines are correct and the USL value for five turbines is 2.9006 kg/s.

Please help me to know why?

Why the USL value is less than the Range value? and when this value effect on flow value? I'm really confused.

Thanks a lot for help and response me.
 
abdi,

First, it might help (very much) if you told us the manufacturer of the HAR<b>T</b> multivariable transmitter you were working on.

Second, if you have six multivariable transmitters, all reading values from the same flow tube/orifice and the same gas temperature and pressure (approximately) but you find one of the settings of one of the transmitters to be off by a factor nearly equal to the error you are reporting (2.9006 / 0.60817 = 4.7694; 6.5 / 1.45 = 4.4828), then it stands to reason that there's something amiss with the one value that's producing the erroneous reading. What will happen if the value is changed to match the other five transmitter values and the output is radically different from what it is believed the value should be? Will the unit trip? Will there just be an alarm--or not? What's the harm in trying to change the transmitter value and seeing what effect it has on the output?

Last, when troubleshooting a problem like this and you have questions about how the transmitter configuration parameters work, it's always recommended to RTFM (Read The Fine Manual) first. You may find that URL and LRL have nothing to do with USL abd LSL--but unless someone knows which transmitter you are working on (and you're keeping that a well-guarded secret from all of us here on control.com) it's going to be hard to say for sure.

HAR<b>T</b> is a communication protocol, not a standard for every configuration definition on every manufacturer that uses the HAR<b>T</b> protocol. There does seem to be a lot of similarity, but then, that's the good thing about standards--there are so friggin' many of them to choose from.

Getting good help from forums like this relies on providing good information. Try to imagine yourself answering--or trying to answer--the question in the way you have phrased and composed it. Do you think you could--if you weren't on site and couldn't see the equipment? We aren't--on-site, nor can we see the equipment. We only know what you tell us, and, well, we need more information.

Help us to help you--and help yourself by researching the manufacturer's manuals and then asking questions about things you need help understanding.
 
J
You can refer to the smart transmitter calibration tutorial found here
http://www.eddl.org/SiteCollectionDocuments/TechPapers/wp_EDDL calibrationtrim.pdf

I agree that it is strange that the URV > USL. This should not be possible. I think if you tried to re-enter the same URV it would be rejected. Did you replace the sensor or circuit board? If the range is set in the circuit board and the board is then paired with another sensor perhaps this can happen.
 
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