Using If command to insert date if certian txt is entered

[helpme_115]

Hi there,

I have the following fields in a form

Barcode
Shelf
Account number
Surname
Inital
Date in
Date out
Lockedby


I want the date to be entered automaticly into either date in or date out when you enter throught it depending on the file location,
If the Shelf was Shelf 124 Then the date in should be entered, but any other location say VO1 then the date should be put in the date out location, have been looking at using

iif(shelf=shelf* now(),"")

but doesnt work


Thanks