We had a building control system in one store, that would accept "occupied" signal from an intruder alarm, and turn on the light and heat. But because the sparks that wired it up didnt talk to the security guys, it was never used.
That will be because its a good idea, but very bad practice.
i shall expalin.
its 5 o clock in the morning, the alarm goes off (for what ever reason) the lights come on the heating comes on etc.
key holder cant be bothered to come out, or does come out but can do nothing with alarm (no break in), calls aalrm company, and agrees engineer can come out anytime today before 18.00, keyholder can also go home to sleep for a couple of hours as early crew have arrived.
Alarm engineer turns up, does what ever and resets the panel.
OH DEAR, the whole place goes dark and starts to get cold, the lights will take about 20 minutes to come back on, duty manager has to close shop (too dark to see)
Reason?
When the alarm went off it switched everything on, keyholder forgot about this, day crew did not know, alarm engineer did not know, but when alarm engineer reset alarm, light / heating over ride contactor is no longer energised, normal heat light switch was not switched on because they were already on, so the whole place goes into darkness.
Thats why most places dont use this function. (and trying toget ana alarm engineer and electrian out at the same time to sort any future problems does not always work 1,st, 2nd, 3rd or 4th time)
