Let there be light! And an engineer travelled across from the mainland, climbed up and down a step ladder to remove ceiling tiles for most of a day, and finally restored proper lighting to our floor in work (after an outage of 12 days).
As well as a PC controlling the signalling between light switches, sensors and the actual lights, there are apparently fifty one controllers embedded across the floor. They have “redundancy built in”. Leading us to understand that if one fails, the remaining fifty carry on regardless.
No sirree. It means that if one goes wrong, the whole lighting management system on the floor is redundant. One failure took out all the lights.
Interesting definition of redundancy.