6/9/2009 10:12 AM  
Posts: 382 Rating: (47) 
Dear all, I have a problem and would like to seek some valuable opinion. I have a of range of inputs as follow: 0 deg = 1000 omhs 150 deg = 100 omhs I would like to take in these signals using analog input card and I plan to use FC105. However the scaling table given between 0 to 150 deg is nonlinear.Thus no good to use FC105 if i want to get accurateconversion. Does anyone have any good ideas orsuggestions? with regards, how come? 
6/9/2009 10:29 AM  
Posts: 557 Rating: (64) 
hi i think, Either you use FC105 or some supporting analog program, your will get a same result. if anybody a different idea, please share.......... regards 
6/9/2009 11:11 AM  
Joined: 2/6/2009 Last visit: 9/23/2022 Posts: 930 Rating: (116) 
Hi, Thelogical formula is, Y= MX+C M = (Y2Y1) / (X2X1) Where, Y = Output X= Input Y2 & Y1 = Output Range X2 & X1 = Input Range M = Slope C = Constant. Hope this will help you. 
Last edited by: saravana kumar@VAESBangalore at: 6/12/2009 9:11 AM_______________________________________________________________ 

6/9/2009 11:13 AM  
Joined: 5/24/2007 Last visit: 6/28/2021 Posts: 284 Rating: (27) 
Hi How Come? Well , what kind of sensor is that. Appears to be a thermistor. If it is so you would be better off using an electronic signal converter as it would be more accurate.The other option is to develop your own XY linearization function which is not so difficult.The third option is you could useone of the mathematicla functions to model the scale. The following should give you some idea how to do it.
HopeI understood your problem correctly. Other wise let us know Krish 

This contribution was helpful to2 thankful Users 
6/10/2009 4:45 AM  
Posts: 382 Rating: (47) 
Dear all, Thank you for the link and the example posted.I will spend somtime looking into it and see how i can go about doing my program. Thanks all andI appreciate your inputs. with regards, how come? 
6/10/2009 5:15 AM  
Joined: 6/28/2007 Last visit: 4/21/2022 Posts: 61 Rating: (4) 
How Come?? i think the FC105 block is the one and it is also written on the same y=mx+c formulation so u will not have much of problems instead of paraameterizing 0 as ur low lit just hae to put 150 as the low limit this will work out for sure... 
Best Regards & Thanks in Advance 

6/10/2009 5:55 AM  
Posts: 382 Rating: (47) 
Hi SPV, I have double using FC105 is because from 0 to 150 deg the omhs result is a curve and it is not straight line or linear. Thats why I put up a post to seek help from anyone who can give me some good ideas or suggestion.. I hope this topic can be a good share information to others in future who face the same senario as me too. Thanks. with regards, how come? 
6/10/2009 6:20 AM  
Posts: 272 Rating: (4) 
I think an analog module with a look up table must be used. As it is righly told , it is a non linear response. 
6/10/2009 7:48 AM  
Posts: 217 Rating: (52) 
Hi, I think you have to plot a graph degree vs. ohms. You got 0150 degrees so you can divide 150 for a suitable scale and plot the graph. Then try to fiend a formula using mathematic (I’m not a mathematic genius perhaps using sin, cos, dy/dx, ect.) and try to implement that formula in step 7. This is like a practical in university. I don’t know weather this is possible with your application. Perhaps will help. Best regards. 
6/10/2009 3:16 PM  
Posts: 2348 Rating: (258) 
1) You need to find formula as mentioned above. 2) Think as 1st approach you should polynomal formula with degree 2 and (if it's not coppesponing) 4 3) For that you can try Excel > Find solution or do leastsquare method by yourself 
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