Use an OnObjectEnter trigger to capture the current field value in a global variable.
This can be a single line script:
Set Variable [$$OldValue ; value: YourTable::YourFIeld]
You can use the same script with multiple fields if you pass GetFieldName ( YourTable::YourField ) as a script parameter to the script and use this line:
Set Variable [$$Oldvalue ; value: GetField ( Get ( ScriptParameter ) )]
Now a validation calculation can test self against $$OldValue to see how they match up:
Self > $$OldValue
could be used to trigger a validation error if the value entered is less than the original. You'll need to modify this if negative values are possible valid entries as an initial value in the field.
Thank you so much! I am able to get it to work with the original field, but am having trouble geting it to work with additional fields.
I found my missing step and now it works for all the fields. Again, Thank you so much!