Every access-controlled door needs a way to tell the system that someone is leaving, not breaking in. A request to exit sensor does that job, and on some doors it also releases the lock. Choosing between a motion sensor, a push button or a switch in the door hardware, and wiring it correctly, depends on the lock and on how people get out. This guide covers the options, the wiring and the setup.
What does a request to exit sensor do?
A request to exit (REX) sensor tells the access controller that someone inside is leaving, so the door opening is not logged as forced. On doors without mechanical free egress, such as most maglock doors, it also cuts lock power. It can be a motion sensor, a push button or a switch inside the lever or exit device.
The two jobs of a request to exit sensor
A door position switch tells the controller whether the door is open. On its own, the controller cannot tell why. The University of Kentucky’s access control and door hardware standard sets out the three possibilities when a door opens: a valid card, someone inside exiting, or a mechanical key or forced entry, and only the last two are alarms.
The REX input is how the controller recognizes the exit. The same standard notes that without it, the system would have to ignore alarms every time someone left, which removes most of the security. That is job one: shunting the forced-door alarm. Job two, on some doors only, is releasing the lock so people can get out at all.
Request to exit sensor types compared
Three device types do the job, and many doors use two of them together.
| Device | How it triggers | Typical door | Watch for |
|---|---|---|---|
| Motion (PIR) REX | Detects a person approaching the door from inside | Maglock doors, hands-free exits, doors with free lever egress | Triggers from people passing by; needs aiming and masking |
| Push to exit button | Deliberate press by the person leaving | Maglock doors as the manual release, low-traffic doors | Users who do not see it; a button wired only to the controller |
| Lockset or exit device switch | Inside lever turned or panic bar pressed | Strike and electrified lock doors with mechanical egress | Must be ordered with the hardware; adds wiring through the door |
The University of Kentucky standard defines that third type, the RX switch inside the lockset or exit device, and calls for it on exterior doors along with door position and latch monitoring. It reports what actually happened at the hardware, rather than inferring it from motion nearby.
REX motion sensor vs push button
A REX motion sensor is hands-free and fast, which suits busy doors and people carrying things. Its weakness is that it reacts to anything it sees: someone walking past inside, a door swinging through its pattern, or an object pushed through the gap from outside if the pattern covers the door edge.
A push button only acts when someone means it. It cannot be set off by passers-by, but some people will not look for it, and on a maglock door a button that only signals the controller still depends on the controller working. That is why maglock doors usually pair a motion sensor for everyday use with a button that breaks lock power by itself.
- Choose motion where people should exit without thinking, and the lock or hardware is otherwise free from inside.
- Choose a button as the deliberate manual release, or where false shunts of the alarm matter more than convenience.
- Choose a hardware switch where the lever or panic bar already lets people out.
How fail safe and fail secure locks change the REX role
The lock’s behavior decides how much rides on the REX. Our maglock vs electric strike guide explains fail safe and fail secure; here is what each means for the exit device.
- Fail secure strike with a lever or panic bar: people leave mechanically, whatever the power state. The REX only shunts the alarm, and many installers do not wire it to release anything.
- Electrified lever, locked outside only: the inside lever is free, so the REX is again an alarm shunt, best taken from the switch in the lever.
- Fail safe maglock: nothing mechanical gets people out. The REX devices are the egress path, so they must cut lock power, not just ask the controller to.
For sensor release doors, the San Mateo Consolidated Fire Department’s egress door locking information sheet summarizes the California Fire Code: the door unlocks on a signal from, or loss of power to, the egress-side sensor, and a manual push to exit device unlocks it independent of the sensor. The mounting and timing details are in our maglock guide. Your adopted code edition and local amendments apply, and the authority having jurisdiction (AHJ) decides.
Mounting and setup that avoids false exits
- Aim the motion sensor at the floor area right in front of the handle on the secure side, usually from above the door.
- Mask the pattern so it does not see the door edge, the gap underneath, glass panels or a corridor where people pass without leaving.
- Set the timers: the sensor’s relay time and the controller’s shunt time should cover a normal exit and door closing, without leaving the door shunted long after.
- Label the button clearly and mount it where a person reaching for the door will see it.
Request to exit wiring: controller, lock and power
Most REX devices give a dry relay contact, and the job is deciding where each contact goes. Follow the device and controller wiring diagrams; the pattern below is the common logic.
- Power the sensor from the access control supply at the voltage on its sheet, not from the lock output.
- Controller input: wire one contact to the door’s REX input and set the input as normally open or normally closed to match.
- Lock power break (maglock doors): wire a second contact, or a second pole of the button, in series with lock power so the lock drops without the controller.
- Fire alarm release: where required, the fire alarm interface also breaks lock power directly.
- Door position switch: wire it to the door’s contact input so the controller can see the door open and close.
Many motion REX units offer more than one output or a changeover contact for exactly this split; check the sheet before you order. Our 22/2 vs 22/4 alarm wire guide helps with conductor counts, and CMR vs CMP cable ratings covers riser and plenum runs.
Then test every path: walk out, press the button, cut controller power, cut lock supply power, and trip the fire alarm input where fitted. Confirm the door state and the event log each time.
Where to find access control products
Browse the Bursma access control category and the wider security, surveillance and control division, including security hardware and accessories and security wire and cable. For REX devices, pricing and availability, ask your sales representative through the Bursma contact page.
If you install for a living, open a Bursma dealer account, or contact the Columbus, OH branch.
Frequently asked questions
Does a request to exit sensor have to unlock the door?
Not always. On a door where the lever or panic bar lets people out mechanically, the REX only shunts the forced-door alarm. On a maglock door it is part of the egress path and must cut lock power.
Where should a REX motion sensor be mounted?
On the secure side, usually above the door, aimed at the area in front of the handle. Mask the pattern so it cannot see the door gap, glass or passing traffic.
Why does my door report forced open when people leave?
The controller is not getting a REX signal before the door position switch opens. Check that the REX is wired to the right input, that the input type matches the contact, and that the sensor sees people early enough.
Can one push button release a maglock and signal the controller?
Yes, if it has two poles or contacts: one breaks lock power directly and the other signals the REX input. Check the button’s sheet and the code your AHJ enforces.