What should an architect check and do next in the truck-scale case?

Check whether all ports and interfaces on the PC are really disabled or unused; check vendor warranties or contracts before changing anything; if changes are allowed, move to a more current security concept using the isolation as input for minimal principle and micro-perimeters; and discuss the risk with IT and with the business owner.

1. Interfaces: are all ports and interfaces on the PC really deactivated or unused? If the scale is counted as part of the system, its communication stays inside the boundary.
2. Contracts: check manufacturer warranties and similar obligations first. Changing the scale PC may be contractually forbidden; if you are bound to the vendor, all you can do is enforce the isolation as far as possible.
3. Modernise if possible: move to a more current security concept. The existing (partial) isolation serves as input for the minimal principle and for building a micro-perimeter.
4. Discuss the risk with the IT manager and the business owner (for example the production manager). IT may carry a feedback risk (Rückwirkungsrisiko) from an insecure PC that has interfaces into the general IT network; the production manager must be aware of possible production outages.