VBA declaring Public variables for use with forms -question for

Hi,
Please can you tell me how I can use Public variables in Access VBA, if I'm working with forms, and giving the variables their values in the form modules.

I've tried declaring the variable in the form modules and in the standard modules. But if the variable gets its value from the form controls and I try to use it in the other modules, it results in a message that the variable is not defined.

I have also experienced this working with forms and with ActiveX controls in Excel.

I have a work-around in Excel, but it would be good to know how to make the Public dimensioning work properly in Access.