Fusion Board Connection

Is there a way to configure the board that if socket connection to PC lost/closed all the relays will be open?

There is no real way to detect a loss of a socket connection, as it is relatively normal to open a socket, control relays, and close a socket. So it’s not really possible to determine if this is intentional or accidental. Use the following methods instead:

  1. Consider using timers to control relays. You will need to send these commands periodically to keep the relay on (you can choose any timing interval you want). If you stop sending relay control commands, the relays will time out and turn off automatically.
  2. You can control relays as normal and use a single timer to turn off all relays when the timer expires. You can reload the timer periodically to keep the timer from expiring.
    Hope this helps.

Controlling relays with timers is only for individual relays? or it is possible to set also a bank state

You can use timers to turn off all relays in all banks as well

What is the commands for timing all relays in bank? I did not find one in the api

To use the Timers, you will need to use Base Station and explore the Reactor features.
This really needs to be configured as a Reactor event into the controller.
You want to look for Fusion Reactor Timer Configuration control panel.
There are tons of timer options that may be used to control relays in many different ways.