populating lookup control based on previous lookup control

Hi

I have two lookup lists. The first one contains a ‘site name’ and the second one contains all the associated ‘equipment codes’ for each site name. I have a form with two list lookup controls. One for the ‘site name’ list and one for the ‘equipment code’ list.

I’d like to filter the ‘equipment code’ list on the ‘site name’ captured from the ‘site name’ lookup list.

Site Name lookup list:
 

Equipment Code lookup list:

Form:

Site Name lookup control:

Equipment Code control:

When previewing the form, based on my faulty control setup, the Equipment ID drop down does not get populated.

What is wrong with my control setup? Or is this even possible?

Thanks

Joanne