Yet another date/ time question 2

[Doc94]

I have taken a few folks advise and created a date field that defaults to todays date and a time field that remains an enterable field on the form. However, I still need to have the date/ time field as I have multiple queries(hundreds) based on it so I am looking to this group for an answer-
On the form or the table, how wouled I combine the dat field and the time field so that it defaults to the date/time field.
I have tried setting the default value for the field in the properties as
=[forms]![fdetailbyfacility]![arrivaldate].[arrivaltime]
Of course this does not work. Any suggestions? The arrival date and arrival time field are entered first, how do I default the date/time field to these two???
Thanks

 

[Doc94]

Thanks Bob that worked great. Except I added it to the LostFocus event for the field.
I may not have explained this form much but it has multiple demographic, time related as well as other fields not just the entry of arrival time. So, in order to help out the data input folks and keep the data clean, I need to run these processes as event procedures.
That said, thanks again, your solution worked great. And I will play with it to add it to other fields that are commonly left "blank" that should not be.
Jon