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Old 10-06-2008, 04:10 PM
extrapilot extrapilot is offline
 
Join Date: Feb 2006
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Bomber-
Your English is much better than my Portuguese, so please do not worry about that!

I have several 203V drives here, and am familiar with their workings- great hardware.

If you do not have a transfer function (i.e. an equation that will output the value based on some simple input), then you will need to setup a lookup table. Normally, that is done using a memory array, so that you would have a cell ID and a value (predefined). It could look just like your example data, with the first column being the cell (row) identifier, and the second the value.

So in the array, if you lookup row 18, you will see value '7' stored there. Now, I dont understand how the numbers you defined function- it appears that the first number is just an increment of 3 over the previous, and the second is some value between 0-9. So how this yields 400 frequencies I am not sure.

Regardless, in my example, you can setup an array and then define the appropriate values as constants. Then, you need to determine 'how' you will communicate with the PIC to tell it which row to use for its new frequency. As I mentioned in an earlier message, there are many ways to communicte with a PIC- so that depends on your requirements. Often, RS232 is the most simple, but there are USB-RS232 converter chips from FTDI that make USB very easy to implement. You could also use a native USB-capable PIC (like the 18F4550), but they are memory constrained.

Do you have a development board you are using? Have you selected a compiler? If not, have a look at Mikroelectronica, they have some very functional development boards, and a compiler you can download for free (just has some limits on the size of the code you compile, but should not be a problem for your app, or at least for testing a smaller array table). There is also lots of sample code included, and on the support forums regarding PWM setup, constant arrays, RS232, etc.

Best,
Rob
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