Read CVC value in function module for Macro

Hi Experts,

I have CVCs in DP planning book at customer location & product level. I have created a Z table to read a field as 'no of days' at customer level.

I want to write a function module, which can be called in Macro. Through that function module , I want to read CVC value for a customer location & based upon it, read no of days from Z table. Kinldy help on how to read CVC value in such function module.

Thanks,

Krutika