Help Needed: Process Level Measurement

Maybe you could contact Exon mobil they are settingup several platforms to run off satelites.

With an inconsistent fluid such as crude oil the measurement of level with a single variable (differential pressure) isn't very accurate. A multivariable transmitter would be much more accurate. Here is an article from the ISA which should help you decide: http://www.isa.org/Template.cfm?Section=Article_In dex1&template=/ContentManagement/ContentDisplay.cf m&ContentID=42977 As for the formula for the URV and LRV of your transmitter system you need to multiply the specific gravity of the fluid (which is referenced to the specific gravity of water) by the height of the fluid column for the URV. The LRV is usually zero and the transmitter can be set to zero at the lowest fluid level regardless of the actual pressure reading. If the LRV needs to be some fluid level other than zero, the formula is the same as for the URV: s.g. * height of fluid column. If you need further assistance feel free to reply to this message.

My best wishes to you… as my concern on the process variables for level measurement is that the displacer type transmitter measures level by having a direct process medium contact to its displacer's weight in other words the displacer submerged within the process medium while remote seal type transmitter is depending on the pressure of a process medium. What is the consequence that may be occurred when process medium and temperature are inconsistent? I assume that the pressure may also vary. Is there any formula that may overcome the problem during process running? Can you explain to me the best way how to get the proper measurement…

The formula depends upon the properties of the fluid being measured, the measurement medium (fill fluid)and several other factors.

The best way to compensate is to use the Multivariable option in the article which I cited in my first reply.

An alternative would be to use a two-capillary system with one side used simply for temperature compensation. Here is an article which discribes this method:
http://www.yokogawa.com/iab/doing150/iab-doing-002 -field-en.htm

The formula I gave you assumes that you are using either inches of water, feet of water, millimeters of water, or meters of water for your pressure units. Most Smart transmitters include the capability of using any of those units. If you choose to use any other units the calculation will be more complex, but the principle is the same. Reference the density of the fluid to the density of water and multiply that result by the height of the fluid column. If you need to use kiloPascals or some other units the conversion factors are easy to find. First calculate the result in inches of water, feet or water, etc, and then use the appropriate conversion factor to obtain the units you need to use.

Rosemount can help you with this technology, if this is the method you wish to use. Is the vessel sealed? Could you use an ultrasonic level unit such as the Milltronics Multi-Ranger?