I'm fitting my first burglar alarm and for magnetic door contacts have purchased FC509MT2 Made by CQR without realising that the 2 at the end indicates that it has two reed switches. My inclination is to use only one but I would be pleased to know what the extra one is intended for. Both reeds appear to be normally closed - that is when the door is shut and the magnet is in close proximity.
Magnetic door contact - two reed switches
- Thread starter NerdNot
- Start date
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A
Alarm
Alarm and access control is one instance of its use.
One contact, two operations.
One contact, two operations.
Ah thank you Alarm. Yes two operations from the single unit makes sense.However I don't really understand what access control is. I imagined it used door locks which were opened by a swipe cards, keypad and the like and I can't quite see how a reed switch can do anything but be an on/off input.
A
Alarm
Hold open indication, door forced indication.
A few things it can be used for.
A few things it can be used for.
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Being pendantic Those reeds are normally open when "de-energised", they close in the ab-normal situation of being "energised" by a magnet being close to them. They would be specified as electrically normally open when purchased.
A
Alarm
Agreed, but he did mention when in proximity to the magnets.
Not the correct terminology as you point out though.
Not the correct terminology as you point out though.
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