I understand what you try to do…You want a panel to combine 2 differents types of devices.
What you have done is the good way.
To increase the refresh, you have to go under “Administration > Dashboard > Panels”.
Edit the “Simple Value Panel” for you “Virtual Value”, go to the “Customisation” Tab.
Edit the property “config.timeout”, set id to “1” and “Save”.
Normally the device will be refreshed every second on your dashboard.
I can create a specific panel for your danfoss to set the value manually but it will not be syncronise. I have to investigate a little bit more.
Just extra questions :
* What kind of NAS do you have ?
* What do you mean by slow ? 1, 2, 3, 5,… seconds ?