Null values cause errors in ProgressBar and other components

NULL values cause errors in Progress bar and other labels.

This happens if an OPC Server returns a null and creates alot of errors in the project.

Can you describe this in more detail?

Do you see errors in both the designer and the client, or just the designer?

I’ve never heard of an OPC server legitimately returning a NULL value…

To replicate just set a SQL tag to a null value. I cant remember the exact syntax.

This was identified during last weeks training class. Travis was able to replicate during the class very easily by using an expression sql tag in somehow setting it to a null value.

I apologize for such a vague response but it is an issue (rarely) but I think it should be resolved.

I will try replicate again in the near future. Been too busy lately.

I think you misunderstood me. I know that it is easy to replicate assigning a null value to something. My point is that I don’t think our currently handling of that situation is wrong.

In the client, you will not get any errors. You’ll get a poor quality overlay over the appropriate component indicating that a type conversion error occurred. I think this is correct.

In the designer, you’ll get the overlay, and a message, which I also think is correct.

My point was that I think that assigning null to an integer value is an error condition, and we’re handling it as such, so I’m not asking how to replicate the issue, I’m asking what exactly you think the “issue” is.

I’m not sure this is totally related to RRNut’s original request but if you have a table “linked” to an SQL query that includes “Null” values and try to reference individual columns in python script it always screws up the values for the columns that occur after,or to the right of, the column with the null value. What we have had to do as a work-around was to ensure that any SQL query result never returns a “Null” in any column.
They do display correctly on the table (i.e. null=blank cell) it is just when accessing the values in script that the problem occurs.

You’d have to give me a working example that demonstrates what you’re talking about - I’m not getting it.

Has there been any change in this area as at ver 7.1.5? beacuse I just tried to replicate the problem & I’ll be damned if I can get it to occur now. :blush:

Not that I know of, but then again, I’m not really sure what you were talking about in the first place :smiley: