how to manipulate input signal? Thanks!!!

[Vss]

Hi,

i am right now dealing with a project related to real-time control. There is a touch screen that can detect the position of items placed on it and convert the position to 4 outputs from its 4 corners. To get the x and y postions on the screen, we need to do a manipulation to the 4 outputs, and the expression for this conversion is quite long that it will be pretty cumbersome to  express it using simple numeric blocks. So i am wondering if there is any block that can do input manipulation with complex expression, just like the "Fcn" block (general expression block) in simulink. Please let me know If you have any idea, i will be most grateful to your help. thanks!!!!!

Xiaofei

[mikeporter]

Yes, it sounds like the formula node will do the trick for you. Note that this node actually implements a very simple C compiler.

Mike...

[Vss]

Thanks Mike! it works!

And then here's another problem: we want a graphical indicator that shows the trace of motion on the plate, i.e. a record of all the previous positions and current position, so we want the x-axis of the plot to be the x-position of the item rather than the simulation time.  So do you know how to make a plot like this? Thanks!!!

[mikeporter]

With an XY Plot you can put whatever you want on the X axis - assuming you have an array of X positions that correspond to the Y positions all you have to do is wire it up. The axis label is editable so you can change it to read what ever you want.

Mike...