Emerson Exchange 365

Rabendra,

Unfortunately I do not have the expertise to comment on how to get to 94% coverage with proof testing. I have forwarded this question on to some others to see if they are able to help address this.

Proof testing with a liquid that is not the actual liquid will always be a little different. I do not know how that affects the coverage. Radars are not calibrated. Their signal return strength is affected by the dielectric of the fluid. A service engineer at the site is recommended to verify that setup is correct. Chambers and nozzles can affect the signal and a service engineer can make sure that the setup is optimized, even when the radar is preconfigured.

In addition to the standard Reference Manual that you referenced (https://www.emerson.com/documents/automation/manual-rosemount-5300-series-high-performance-guided-wave-radar-en-76166.pdf), we do have a Commissioning and Validation Procedures Reference Manual as well (https://www.emerson.com/documents/automation/manual-rosemount-5300-series-commissioning-validation-procedures-for-rosemount-radar-en-79458.pdf) that you may find helpful.

We do also have a tech note that covers some info on installed radar in chambers:

https://www.emerson.com/documents/automation/technical-note-guidelines-for-choosing-installing-radar-in-stilling-wells-bypass-chambers-en-89362.pdf

You can contact me directly at lydiacamiller@emerson.com if needed or contact your local sales person to assist you with further technical help.

In reply to Lydia Miller:

Rabendra,

It seems from your question that the primary goal is ensuring that the GWR is properly configured for the application. Is that the case?

In your question, you refer to the proof test. Normally, I think about using the proof test for safety-instrumented systems, though it could be used in non-SIS applications. Does this application call for safety-instrumented devices?

If you are still looking for assistance here, I can be of more help if I understand the answers to these two questions.

In reply to Rabendra Aldi:

Ok, thank you! So let me restate my understanding of your questions and them respond to them.

1) If you use the procedure outlined in section 8.8.2 of the Rosemount 5300 manual, but you perform the test using diesel, will the results still achieve 94% coverage?

Keep in mind that section 8.8.2 is written specifically for devices that have SIS approval. These devices must have either "QS" or "QT" in the model number.

There's a statement in the procedure: "For a valid result, always perform the proof test on the product that will be stored in the tank while the
device is in operation." Since you are proposing to use diesel for the test, but diesel is not the same process fluid as will be used when the vessel is in operation, then it is not possible to assure 94% coverage nor is it possible to estimate what the actual coverage will be.

2) Is it possible to use this same procedure to verify coverage of the interface measurement?

Users of guided wave radar in safety-instrumented systems typically want to achieve a safe shut-down of the process based on the level measurement rather than interface. The goal almost always is to ensure the device will detect a high level so that a spill can be prevented. Alternatively, they are looking to prevent an unsafe operating condition (either high or low level) using the surface level measurement as the evaluation criteria. Therefore, the procedure is specifically written to only apply to the level (surface) measurement and is not applicable to cover the interface measurement.

This may be more detail than you want or need, but let me explain this a bit more. A guided wave radar detects locations along the probe where microwaves encounter an impedance change. It's possible to locate with high accuracy when the impedance change occurs between the vapor space and the liquid surface. Microwaves travel through the vapor space almost entirely impeded. But, once they pass through the upper fluid, they will slow down depending upon the dielectric constant of the upper fluid. That dielectric constant is a configurable parameter supplied by the user. The manufacturer has no way to quantify uncertainty in the interface measurement when the uncertainty is determined by a user-configured parameter.