Forms for history and new data?

[Jebuz]

Hi,

Here is my real world setup I am trying to model. I have 3 tables with data
(mainly serial #'s and model #'s) of equipment that is all related to each
other somehow. I have a table called 'Work Orders' that is going to be used
to track and create maintenance requests needing to be done on the above
equipment . The configuration of the equipment must be shown on the work
order. However the configurations may change (in which I will make tables
for histories of each of the 3 equipement tables). Here is an example of the
tables.

table: 'Sites'
fields: ID#, Name, Location
data: 203342 , DB5, 5th & Arthur

table: 'Monitors'
fields: Serial# Model# Sensor1 Sensor2 Sensor3 fkSiteID
data: 34673 12345 OX4 OX5 LV5
203342

table: 'Sensors'
fields: Serial# Type
data: OX4 UV
data: OX5 AV
data: LV5 UV

So a Site has 1 monitor at it with the monitor having 3 sensors.

I am having troubles with creating a form for viewing or creating new work
orders. I can view ones just fine if I put fields in a Work Orders table
like fkSiteID, fkMonitorID, fkSensorsID etc. The problem is I don't want
the previously created work orders to change when I modify for instance a
monitor having a different sensor set-up. Work orders must show a "history"
of maintenance. Also when creating a new work order, if I put all the
duplicate fields from equipment tables in the work order table, how do I let
the user select from the current equipment serial #'s? Since noone can
remember serial #'s.

Sorry for the lengthy post but I just tried to explain all the details of my
problem best I could. Thanks to all who read and reply!! This is driving me
crazy!