7/2/2014 9:05 AM | |
Joined: 12/1/2009 Last visit: 9/5/2024 Posts: 672 Rating: (147) |
Dear laurensvl, Just an idea I faced a similar problem with a radar measurement long time ago. Wheneverthere was somefoamfloating on the surface of the waterwe werereceiviinga wrong signal. Maybe you havean option on theE+H sensor for some calibration. We replaced the radar with a pressure based level measurement. Best Regards. |
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7/2/2014 12:16 PM | |
Joined: 1/5/2011 Last visit: 6/15/2024 Posts: 815 Rating: (123) |
Hello laurensvl, can you share the defined parametersof your scaling function with us? You could have following issues: -your lower limit isn't set correctly. - your analog input card is set to 0-20mA while your sensor is 4-20mA. If the analog input range of your card isn't set correctlyit would give you a different slope for both cases: Case 1)Input range card 0-20mA, corresponds to 0-8300mm 0-20mA = 0-8300mm (Lo_lim = 0, Hi_lim = 8300) => Slope = ((8300-0)/(20-0)) = 415 Case 2) Input range card 4-20mA, corresponds to 0-8300mm 4-20mA = 0-8300mm (Lo_lim = 0, Hi_lim = 8300) => Slope = ((8300-0)/(20-4)) = 518.75 Most likely this will not be the issue since the result you have at 7,08mA is 1598mm, which would give you case 2, which is correct. If you are dealing with case 1 you would have 2938.2mm at 7,08mA. So another thing is could be (most likely) is the LO_LIM that isn't set correctly. I think 4-20mA doesn't represent 0-8300mm, but rather 597,2136 - 8300mm. I've attached agraph which shows the result you are having (case 1) and the result you should have (case 2). If you are sure your analog sensor has a lineair measurement you should change the lineairization by changing the slope. I guess changing your slope (by tweaking the lower limit)could solve the problem. Check attachment for more info (sorry if any mistakes were made ). Kind regards, Jens AttachmentChangeLimits.pdf (272 Downloads) |
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