Well, Topsy's method is better than mine, but I thought you really want the data to be stored in an external file "to be editted or so!".
Any way, avoid using files if you don't want them.
And about my method, you have to convert the "string" output to be "numeric" before it is used by the AO function.
Good luck
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Ayman Mohammad Metwally
Automation Engineer
Egypt - Cairo