Endress Hauser Level Transmitter (Incorrect Level reading)

Hello,
I have an endress hauser level transmitter FMR51, which is a free wave radar type transmitter. It is installed in a bulk storage tank to measure the base oil in the tank. The transmitter is installed in a stilling well.
Problem is, I cannot get the correct level reading. I have configured the instrument, input all the required parameters. Even tried mapping function of the transmitter. But the transmitter does not show correct levels at any point. When I configure the transmitter in empty tank condition (using empty tank mapping), I get 0 or 5 or 6 mm level on the display. But as level rises in the tank the error increases with it.
Please suggest a solution. I know the level is incorrect beacuse there is a glass gauge installed on the tank, from which we can manually read the level of tank, and it does not match with level of transmitter. (at some point the transmitter shows between 500-1000mm higher level than the gauge, and sometimes it shows 500-600 mm less level).
 
Hello,
I have an endress hauser level transmitter FMR51, which is a free wave radar type transmitter. It is installed in a bulk storage tank to measure the base oil in the tank. The transmitter is installed in a stilling well.
Problem is, I cannot get the correct level reading. I have configured the instrument, input all the required parameters. Even tried mapping function of the transmitter. But the transmitter does not show correct levels at any point. When I configure the transmitter in empty tank condition (using empty tank mapping), I get 0 or 5 or 6 mm level on the display. But as level rises in the tank the error increases with it.
Please suggest a solution. I know the level is incorrect beacuse there is a glass gauge installed on the tank, from which we can manually read the level of tank, and it does not match with level of transmitter. (at some point the transmitter shows between 500-1000mm higher level than the gauge, and sometimes it shows 500-600 mm less level).



Check whether the still well fabrication specs and the beam angle of the radar transmitter as recommended in the manufacturer specs, is in line as per the site installation. Also be fully sure that the manual gauge glass reading is correct or not. If you have any other way of checking it manually by a dipstick , perform that.
 
Check whether the still well fabrication specs and the beam angle of the radar transmitter as recommended in the manufacturer specs, is in line as per the site installation. Also be fully sure that the manual gauge glass reading is correct or not. If you have any other way of checking it manually by a dipstick , perform that.
Still well was fabricated and installed as per the E&H manual recommendation. I performed a dipstick test once on tank that doesn't have a glass gauge, and the level reading on the transmitter did not match dip stick reading.
 
What is the size of the transmitter/antenna size?? And what type of antenna is it??? What is the measuring height of the tank?? What is the process medium that you are measuring?? Is the tank bottom a flat face or dished out?? The difference in measurement as you said in your first post...is it happening at/after some particular level during when the process inside the tank is constant or is it happening during tank filling/unfilling ??? Is there anything coming (obstruction) in between the beam angle of the transmitter?? Have you selected the proper die-electric constant???
the density of the medium through which the waves are travelling...is it constant and same during all instances of measurement???
 
Transmitter size= 100mm (4in)
Antenna type= free wave rada
Measuring tank height= 3048mm(10ft.)
Process medium= base oil used for in lubricants
Tank bottom= dished out
Obstruction= there can be no obstruction since the transmitter is installed in a stilling well
Die-electric constant= There were 2 possible settings, one was water-based medium, second was "Other". I chose other, since my product is oil.
I cannot confirm the density of medium.
The level reading is never correct, either during filling/emptying process or when the product is just sitting in the tank.
 
Did you do an interference echo mapping??? If yes , cross check again that you have saved it and to use it as a reference curve....
See the whole point of using a still well is that the high frequency waves are guided by the still well to reach to the level of the actual process media present in the tank and then get reflected back from it in an efficient manner, same concept of a coaxial probe Gwr....Now if you are not getting the proper result at any point(as you said earlier) , then there is obviously an interference echo from the still well or maybe from somewhere else , who knows what it is...but whatever it is, that's surely corrupting ur measured signal...!! Also the stillwell is after all a man made thing...who knows, some kind of irregularity might have crept in during the fabrication or the welding process..!
So, remove the stillwell and install it directly freely and check whether the level reading is correct or not. Adhere to the max tank nozzle height as given in the specs and radar beam width during the installation.
Also if it is a 4 wire tx , check whether the display on the Tx and mA conforms to each other or not...many a times I have faced this problem with 4-wire Tx's due to different ground potentials,i.e. measurements are correct but mA is different at receiver end due to different ground potential.
 
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