lookup table in simulink

Hi All ,

I am new to simulink . I am trying to create a look up table with certain correction factor values . Problem that I face is that my breakpoints are not evenly spaced so when I use simulink 1D lookup table block , I get error . Any work around for this problem .

Thanks in advance

Answer 1

[Jim Riggs]

There is no reason that non-uniform breakpoint spacing should be causing an error with the 1D interpolation function. I think that the error is from some other cause. You need to provide more information.

How are you defining the interpolation table (can you show the values)

What exact error message is being given?

[bhaskar ponnana]

Hi Jim , Thanks for the reply , Sorry for the confusion I would like to rephrase my question .

My table data is monotonically increasing and where as my breakpoint data is montonically decreasing ( as per datasheet) . Any way to implement this in simulink look up table options .

Below is the error i get

Values of 'BreakpointsForDimension1' in <model_name>' must be strictly monotonically increasing. The problem occurs at element 2. Change the breakpoints data or use the fixed-point tools such as Auto Scaling or Fixed-Point Advisor to determine a different parameter dialog type.

my data:

Table data: [384 440 506 583 674 782 912]

Breakpoint data: [15 10 5 0 -5 -10 -15]

For now I am trying using matlab fuction block with interpolate function (https://www.mathworks.com/help/matlab/ref/interp1.html) .

[Jim Riggs]

OK. It's not the breakpoint spacing, but that the values are decreasing.

You can simply flip the table so that the breakpoints are increasing.

Also, the requirement for monotonicity applies ONLY to the breakpoints. The data values associated with them can be anything.