Hi there, I haven´t problems with Chart refresh but I did use just a couple of channels, don’t know with a lot of channels.
If you are talking about writing period (2 secs), in my case is enough but, sometimes, is necessary a lower period and is a good idea/practice the use of a ‘tick’ variable on every channel then you can select which one save and when, also less than 1 second is a common option in scadas.
Hope you can apply this changes on future versions, I know you have a lot of work with this project but you are on the right way 🙂