Is there any documentation that explains how to set up Validation rules both Fixed and Expressions?
Check out the "Validation" section on the page below under 'rules':
https://manual.pvxplus.com/page/NOMADS%20Graphical%20Application/Creating%20Panel%20Controls/Multi-Line%20Control/Multi-Line%20Properties.htm
Here is what you will find:
Input validation range and/or values (comma-separated); e.g. A, C, R-T. Can be a Fixed value, string Expression or Dynamic. (Dynamic is available only when a data Class is entered.) If using Property Sheets and setting Rules to Dynamic, the Validator and Formatter properties will automatically be set to Dynamic.
In data dictionary (2017) we have the option to validate rules using expression. I have tried several different ways to enter an expression (for a numeric) but always get an invalid expression message?
Can you describe the validation rule you are looking to apply?
For example if you want the validation to be that the value must be between the values held in %Min_days and %Max_days then your expression would be:
str(%min_days)+"-"+str(%max_days)
Let us know what you are trying to achieve.