Radar level gauge
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The Emerson radar level gauge is used to measure the liquid level in a storage tank. When material is fed into the tank, the level instead of rising keeps dropping, going from 0.2 meters down to 0. Powering off the device and performing a new scan had no effect; the gauge continued to show a decreasing level, all the way down to 0. The pump did not stop during this period. After the level dropped to 0, power was cut off several times and new scans were performed, and the radar then displayed a normal level. Why is this happening?
At low liquid levels, radar waves are subject to interference; the reflections from the bottom of the tank may be stronger than those from the product； Or there may be obstacles at the bottom of the tank, such as heating coils, which cause reflected waves ； Once the liquid level rises, the interference will naturally disappear ；
First, consider what type of tank you have and whether there is any disturbance from stirring. Also, determine what type of radar you are using – horn-type, cable-type, or rod-type. Check whether there are floating decks on the tank, or whether there are heat sources such as heating coils at the bottom of the tank that could cause interference, as well as any mechanical disturbances. After ruling out these factors, I recommend that you install guide tubes if possible.
There is interference at the bottom of the tank; it might be due to stirring blades or forces from the heating plate. It is advisable to install a guide tube for radar level gauges
Reply to 4# engineer021: If there is interference, why does it keep decreasing to 0 and then stop changing? ? As soon as I turned off the power, the liquid level rose sharply to the normal level of 2 meters; turning off the power before it dropped back to 0 had no effect
At 4-20 milliamps, the zero level is set at 4.