Hi,
First time posting. I am trying to be able to change the YMax value of a chart from a UI input. I have got it half working however every time i enter a Y value on the UI it also plots this on the chart.
You should send only msg.ui_control and delete msg.payload
You forgot to delete the payload property of msg object
And you'll need still return msg object (it is my bad explanation at first reply. sorry)
correct will be : msg should carry only ui_control property
msg.ui_control = {control stuff here}
delete msg.payload
return msg
If the ymax is only thing you'll need to change then it is reasonable to use the change node with move rule configured like this

Perfect, thank you very much for your help