Level Indicator for Dry Lactose - Sanitary application

Have a look at the blanking distance. It could be that this parameter isn't correctly set.

We already checked it.

Thks.

Then either it isn't "seeing" the surface or the indications are real (rat-holing? bridging?). Have you tried weigh-cells instead of radar?

What sort of tank cone bottom? vibrators to help unloading?

What sort of transportation system conveyors or air?

Do you need to know actual level or just high & low level? I've seen very good results using RF probes from http://www.bindicator.com/ for corn & wheat flour, sensitive enough to tell the difference between loosely packed & compressed flour.

Load cells will give you very accurate results, you will only need to figure out how to isolate the in & out.

I worked over twelve years at Magnetrol as an Senior Electrical design engineer. I am very familar with the Guided Wave Radar product line. Guided Wave Radar (GWR) is a very useful level measurement technology, simple to install with very few problems. It is not perfect and some applications can be problematic. The key with GWR is using the right probe for the material.

I expect that you are trying to use a GWR unit with sanitary approved single rod probe. This probe is design to find the top surface of a moderate dielectric material (er>10). Since you are seeing the probe offset, most of the radar pulse is not reflecting off the top surface but instead must be penitrating though the material and reflecting off the end of the probe. I expect that Dry Lactose has a low dielectric.

The End of Probe reflection is of opposite polarity of a level reflection. If the material being measure is a too low of dielectric the top surface reflection will dissapear into the much larger End of Probe pluse when the top surface is too close to the end of the probe. All this information is in the manual which can be downloaded from www.Magnetrol.com

Have you tried setting the level to Fix? The End of Probe Pulse might have some negative polarity components that could be confounding the level constant fraction discrimator.

Maybe the End of Probe circuitry is not operating properly. You can disable the End of Probe detection by doubling the lenght of the probe setting. There was blanking circuit that blanks out the first half of the scan. Double the probe lenght and see if you can measure lower on the probe. You should not operate in this extended probe mode as the unit can falsely lock of the End of Probe as a real level and the system will be out of control.

Have you contacted your Magnetrol Rep? Magnetrol has a very good field service department.