Reaction on YouTube video "Modify DDT Structure in Control Expert 15.2 without Stopping M580 PLC"

[dnordenberg]

This video took me a bit by surprise, is nothing to be proud of... it is certainly not a good advertising video for Control Expert/SE PAC PLCs... I actually find it quite embarrassing 😞

https://www.youtube.com/watch?v=XPjjP_lwfhw

It doesn't show us how to do smart and efficient things in Control Expert like many of the other YouTube videos... Instead it is demonstrating what is clearly a deficiency in Control Expert that it can't modify a DDT while it is being used and is then trying to prove Control Expert wrong by showing it can very well be done using a (not so nice) workaround which clearly shows that it is not a hard to overcome technical limitation in the software that it doesn't just allow it in the first place. I just want to say, please focus on the usability of the software instead of having to teach us workarounds for a problem that shouldn't even have been a problem from the start 😞

Kind regards

David

[Trinxs1]

I would add a caution to this video.  The demonstration shows a workaround which is valid for one scenario, i.e. where you can delete the instances, add child elements to the DDT and then re instantiate with the same names and hence maintain the project, without further change.  The demonstration does not explain the limitations of the modification.   For example, what happens when you change an element to a different type? What happens when you delete an element?  What happens if the elements are located to a memory address and external devices are accessing the memory locations?

It is unfortunate that we do not support changes to a DDT when it is instantiated and I would certainly like it if we could, but please test the situation on the bench before you try to apply this in a live situation.  There may be some good reasons why this is ability is not supported.

I would view this as a trick that in some limited situations works and may get you out of a difficult situation rather than a validated approach that can be applied to all situations.