jerlands Posted April 13, 2015 Share Posted April 13, 2015 I want to change out my N/C (circuit complete when magnets together) contacts that came with the garage kit for N/O (circuit open when magnets together) but am unable to locate one. I don't want to mount the sensor to the floor but overhead and would like similar in design to what I have (4" X 1/2" X 1/2".) If anyone has lead to this beast I'd appreciate a pointer to it. Thanks, Jon Link to comment
Xathros Posted April 13, 2015 Share Posted April 13, 2015 This is what you want: http://www.smarthome.com/seco-larm-sm-226l-3-magnetic-garage-door-contact-switch.html Can be wired either way. I have mine mounted at the top of the door frame. -Xathros Link to comment
jerlands Posted April 13, 2015 Author Share Posted April 13, 2015 Thanks for the info and the pic.. I had looked at the SM-226L-3 on Smarthome's site before but read it was floor mounted and not seeing any dimensions I envisioned it much larger.. I see on SECO-LARM's site it's only 4 3/8" x 1 3/4" x 7/16" which is less in height than what came with the garage kit i.e., 4" X 1/2" X 1/2" Jon... Link to comment
stusviews Posted April 13, 2015 Share Posted April 13, 2015 Our SM-226L-3 measures 4-3/8" x 1-1/2" x 1/2" Link to comment
io_guy Posted April 15, 2015 Share Posted April 15, 2015 I want to change out my N/C (circuit complete when magnets together) contacts that came with the garage kit for N/O (circuit open when magnets together) but am unable to locate one. I don't want to mount the sensor to the floor but overhead and would like similar in design to what I have (4" X 1/2" X 1/2".) If anyone has lead to this beast I'd appreciate a pointer to it. Thanks, Jon FYI,Your logic is reverse. A NO sensor is complete when magnets are together. Link to comment
jerlands Posted April 15, 2015 Author Share Posted April 15, 2015 FYI, Your logic is reverse. A NO sensor is complete when magnets are together. Ok.. that's really confusing I would think the normal state for the sensor is where both magnets are together? if that's true then if both magnets are together a normally open contact should be open (no current flow) in that state? There's also the issue with the circuit... a normally open circuit is true when there is no continuity? a normally closed circuit is true when there is continuity? I'm not certain about any of this but the switch I have now is closed when together (continuity)... I'm calling that normally closed and my I/OLinc is telling me the sensor is ON (true) in that position so it seems to me the circuit of the I/OLinc is normally closed? Link to comment
Brian H Posted April 15, 2015 Share Posted April 15, 2015 The confusion on magnetic sensors is depends on the application. As an Electronic Technician. I refer to a magnetic switches resting state with no magnet present. Magnetic Switches when called out in security applications. Is in the state when the zone is not violated. So my NO switch when in a security setup is a NC. As it is closed when the magnet is next to it and not the zone is not violated. Some vendors are not too clear on their descriptions. Link to comment
jerlands Posted April 15, 2015 Author Share Posted April 15, 2015 The confusion on magnetic sensors is depends on the application. As an Electronic Technician. I refer to a magnetic switches resting state with no magnet present. Magnetic Switches when called out in security applications. Is in the state when the zone is not violated. So my NO switch when in a security setup is a NC. As it is closed when the magnet is next to it and not the zone is not violated. Some vendors are not too clear on their descriptions. Thanks, after your reply I took the time to Wiki "reed switch" http://en.wikipedia.org/wiki/Reed_switch and it basically says the same as you.. normal state is when no magnetic field is present. Jon Link to comment
stusviews Posted April 15, 2015 Share Posted April 15, 2015 In most contexts, the normal state is without any external influence. For a magnetic switch, it's apart fro the magnet, for an electrical switch, it's without power. Edit: for a push button, it's the un-pushed position. Link to comment
MustangChris04 Posted April 15, 2015 Share Posted April 15, 2015 I use the following on my garage:http://www.amazon.com/gp/product/B008SKTWVC/ref=oh_aui_search_detailpage?ie=UTF8&psc=1 Link to comment
jerlands Posted April 16, 2015 Author Share Posted April 16, 2015 In most contexts, the normal state is without any external influence. For a magnetic switch, it's apart fro the magnet, for an electrical switch, it's without power. Edit: for a push button, it's the un-pushed position. I guess the bottom line here is I would need to use a NC switch for the IOLinc to see the sensor as OFF when the garage door is closed? Link to comment
LeeG Posted April 16, 2015 Share Posted April 16, 2015 The magnetic switch has to be "open/not shorted" for the Sensor to be Off with door closed. Up to you whether that is considered NC or NO. Devices used for security are named one way, for industry use they are named the opposite. For the NC/NO magnetic switch that would be the Black/Red wires. Link to comment
stusviews Posted April 16, 2015 Share Posted April 16, 2015 That's correct. When there is nothing influencing the switch such as a magnet, a NC switch would send an On signal (when connected to an I/O Linc). When then magnet is present the NC switch contacts open resulting in an Off signal. Link to comment
jerlands Posted April 16, 2015 Author Share Posted April 16, 2015 That's correct. When there is nothing influencing the switch such as a magnet, a NC switch would send an On signal (when connected to an I/O Linc). When then magnet is present the NC switch contacts open resulting in an Off signal. That's good to know.. even though I have the SECO-LARM SM-226L-3 (NO/NC) on the way I needed to clear that up in my head Thanks, Jon Link to comment
stusviews Posted April 16, 2015 Share Posted April 16, 2015 There's a lot of confusion regarding NO vs. NC. Even on security device web sites, you'll find the same switch described differently. But. from an engineering/electrical/wiring perspective. normal is the uninfluenced position. Most switches are shipped in the normal position. Another example in addition to post #10 is a plunger switch, the kind that you push in and it clicks in place. Push again to click out. The normal position is with the spring relaxed (i.e., out). Edit: most security system use a "closed circuit." That's not the same as "normally closed." Therein is the confusion. Link to comment
shannong Posted April 16, 2015 Share Posted April 16, 2015 If Smart Labs would make the sensible and simple change to the IOLinc so that reversing the trigger also reversed the state when queried it wouldn't matter much. Link to comment
Xathros Posted April 16, 2015 Share Posted April 16, 2015 Or at a minimum, go back to selling the dual contact Seco-larm switch with the garage kit. -Xathros Link to comment
jerlands Posted April 16, 2015 Author Share Posted April 16, 2015 Edit: most security system use a "closed circuit." That's not the same as "normally closed." Therein is the confusion. That's probably why I'm seeing so many NO magnetic switches and so few NC... Link to comment
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