> why can't they design physical safety relays/cutoffs?
They can and they do. Or at least "they" used to. Nowadays such safety devices are very often software enabled. Because it's cheap and also because it checks a box on the marketing brochure that every customer wants: "Software upgradability for lower maintenance cost and reduced down time." Oh the irony.
They can and they do. Or at least "they" used to. Nowadays such safety devices are very often software enabled. Because it's cheap and also because it checks a box on the marketing brochure that every customer wants: "Software upgradability for lower maintenance cost and reduced down time." Oh the irony.