Rechnernetz

German: Rechnernetz, contrast with Netzwerk.

In German technical documentation, Netz typically means a power mains/grid (depending on which side of the Atlantic you're writing for) - or more abstractly, "power". Netzwerk means "network". Where it gets slippery is Rechnernetz vs. Rechnernetzwerk.

So: Rechnernetz = computer power or computer power grid, perhaps.

The context in this case is a test bench that has separate power to the computer (for test data) and the bench itself - the emergency stop shuts off the bench, but not the computer, so you don't lose data. I was about 2000 words in before I realized that we weren't talking about the computer network - of which there is also one. Built-in hub, even.