SDC MD-31D Series Request-to-E...
IN STOCK (leaves warehouse same day if ordered before 3pm ET)
$276.00
$178.09
SDC SDC MD-31D Series - Request-to-Exit PIR Motion Sensors SDC-MD31

SDC MD-31D Series Request-to-Exit PIR Motion Sensor with Dual Voltage Auto-Sensing

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Model: MD-31DOW
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$276.00
$178.09
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SDC MD-31D Series Request-to-Exit PIR Motion Sensor with Dual Voltage Auto-Sensing

Code-Compliant Passive Infrared Detection for Access-Controlled Egress Doors

The SDC MD-31D series motion sensor is a passive infrared detector specifically engineered for request-to-exit applications on access-controlled egress doors. This compact 7"; x 1-3/4"; x 1-7/8"; unit features auto-sensing dual voltage operation at 12VAC or 24VAC with an internally pointable coverage field that provides 5' x 6' coverage at 7' height or 10' x 12' coverage at 15' height when angled 14 degrees down. The MD-31D projects a wraparound ";U"; pattern down and away from the door to inhibit tampering while ensuring reliable detection for code compliance.

Professional Features & Benefits

  • Adjustable Coverage Field: Internally pointable detection provides 5' x 6' coverage at 7' height or 10' x 12' coverage at 15' height when angled 14 degrees down for flexible installation options.
  • Auto-Sensing Dual Voltage: Operates on both 12VAC and 24VAC systems with automatic voltage detection for versatile system integration.
  • Tamper-Resistant Design: Wraparound ";U"; pattern projects down and away from the door to inhibit tampering while maintaining reliable detection.
  • Code Compliance Certified: Meets IBC 1008.1.3.4, IFC 1008.1.3.4, NFPA 101 7.2.1.6.2, NFPA 1.15.5.3.2, BOCA 1017.4.5, and SBCCI 1012.7 requirements for access-controlled egress doors.
  • Relock Time Delay Function: Built-in RTD feature provides controlled timing for secure re-engagement after exit detection.
  • Versatile Mounting Options: Frame header, wall, or ceiling mount configurations accommodate various installation requirements.
  • Failsafe Operation: Code-compliant failsafe mode ensures proper egress functionality during power interruption (MD-31DOW variant).
  • Wide Temperature Range: Operates reliably from -20°F to 120°F for demanding environmental conditions.

Technical Specifications

  • Commercial/Residential: Commercial
  • Department: Door Hardware
  • Electronic: Yes
  • PDF:SDC Full Catalog: https://zensupply.com/content/pdf/lcn/CondensedHardwareBrochure
  • Product Category: Electronic Access Controls
  • Product Dimension: 7"; x 13/4"; x 17/8";
  • Product Group: Electronic Access Controls
  • Product Model: MD-31D
  • Product Subgroup: Sensors, Switches, Relays and Timers
  • Product Substrate: Plastic
  • Product Type: Motion Sensors
  • Product Voltage: 12VAC, 24VAC
  • Series: MD-31 Series
  • Subcategory: Motion Sensors
  • Temperature Range: Minus 20 Degrees F to 120 Degrees F

Professional Applications

  • Commercial Building Security Systems
  • Healthcare Facility Access Control
  • Educational Institution Safety Systems
  • Industrial Facility Monitoring
  • Government and Municipal Buildings
  • Emergency Exit Compliance
  • Multi-Tenant Residential Properties

Why Choose SDC Quality?

SDC MD-31D series motion sensors deliver professional-grade reliability with passive infrared detection technology rated for operation from -20°F to 120°F in demanding commercial applications. Certified compliance with IBC, IFC, NFPA, BOCA, and SBCCI building codes ensures proper egress functionality while auto-sensing dual voltage operation provides flexible system integration. Engineered for demanding access control applications where dependable code-compliant performance is essential.

Manufacturer Resources

SDC Full Catalog

Product Specs

Subcategory:
Motion Sensors
Series:
MD-31 Series
Product Group:
Electronic Access Controls
Product Subgroup:
Sensors, Switches, Relays and Timers
Product Type:
Sensors
Commercial/Residential:
Commercial
Temperature Range:
Minus 20 Degrees F to 120 Degrees F
Electronic:
Yes
Product Model:
MD-31D
Product Voltage:
12VAC, 24VAC
Product Dimension:
7" x 13/4" x 17/8"
Product Category:
Electronic Access Controls
Product Substrate:
Plastic
Department:
Door Hardware

SDC MD-31DOW – Frequently Asked Questions

1) Will the SDC MD-31D request-to-exit sensor run on my 12VAC access control power supply, or do I need 24V?
Either works. The MD-31D auto-senses and operates on 12VAC or 24VAC, so you wire it to whatever the panel or supply already puts out without setting a jumper or ordering a voltage-specific part. Note the AC part: this is an AC-input device, so if your board only offers a filtered DC output for accessories, that is the wrong tap for it.
2) How much floor area does the MD-31D PIR cover, and how high can I mount it?
Coverage scales with mounting height. At 7 feet the MD-31D throws a 5 x 6 foot field; at 15 feet, angled 14 degrees down, it opens to 10 x 12 feet. The head is internally pointable, so you aim the pattern after the housing is mounted rather than shimming the box. For a single leaf at typical header height you are in the small-pattern range, which is usually what you want, since a wide field on a low door picks up traffic walking past the opening and unlocks it for no reason.
3) Will an SDC MD-31D fit above a door in a narrow header, and what are its dimensions?
The MD-31D measures 7 x 1-3/4 x 1-7/8 inches, so it needs about 7 inches of continuous flat surface and clears roughly 1-7/8 inches off the mounting face. That fits most aluminum and hollow metal headers, but check the projection against a door that swings toward the sensor or against overhead closer arms and stop-mounted hold-opens. Frame header, wall, and ceiling mounting are all supported.
4) Is the SDC MD-31D the same thing as a door-mounted safety sensor for an automatic operator?
No, and this is a common mix-up on a bid. The MD-31D is a request-to-exit PIR: it tells the access control system somebody is approaching from the egress side so the lock releases legally. A safety sensor like the LCN 8310-804-1, which uses leading edge detection and mounts on the door itself, is there to stop or reverse a powered operator before it hits a person. An automatic sliding or swinging entrance with an electrified lock often needs both, wired to different inputs. Buying one and calling it the other leaves either the egress path or the safety circuit unfinished.
5) I need a request-to-exit PIR that runs on 12 or 24VDC, not AC. What should I order?
Not the MD-31D. It is a 12VAC / 24VAC device. For a DC accessory bus, the Dortronics 6612 Series request-to-exit PIR is the DC part, listed at 12/24VDC with an adjustable 1 to 120 second time delay in a slim 7.1 x 1.65 x 1.65 inch housing. Most modern access panels and magnetic lock supplies put out DC on the accessory terminals, so confirm what your board actually delivers before you pick between the two.
6) Does the SDC MD-31D release the door if the building loses power?
Failsafe operation on power interruption is specific to the MD-31DOW version of the MD-31 Series, not to every model in the family. If your AHJ is requiring the egress path to open on loss of power, order the OW variant and say so on the purchase order. Also remember the sensor is only one contact in that chain, the lock itself and the power supply determine whether the opening actually goes free on a power drop.
7) The access control panel at the door only supplies DC. Is there a request-to-exit motion sensor for that?
Yes. The Dortronics 6612 Series request-to-exit PIR motion detector is specified for 12/24VDC, so it drops onto a DC supply directly. The SDC MD-31D is built the other way around, with auto-sensing operation on 12VAC or 24VAC. Both are passive infrared request-to-exit detectors for the header above an access-controlled egress door, so the decision here is the power at the door rather than the detection method.
8) Can the LCN 8310-804-1 sensor be used in place of an SDC MD-31D for request-to-exit?
No, they do different jobs. The LCN 8310-804-1 is a door mount safety sensor with leading edge detection technology, mounted on the door leaf itself to watch the swing path and stop or reverse an automatic operator before the door strikes someone. The SDC MD-31D is a request-to-exit passive infrared detector that reads a person approaching the door from the secure side and signals the access control system to release. On an automatic door with card access, both functions are often present and both devices get installed, but a leading edge safety sensor will not satisfy the request-to-exit requirement and an RTE sensor will not provide swing path safety.
9) What keeps someone from tripping a request-to-exit PIR from the secure side by sliding something under the door?
Pattern geometry is the defense here. The MD-31D projects a wraparound U-shaped field down and away from the door rather than a flat blanket across the opening, which is what inhibits tampering from the far side while still catching a person walking up to exit. Aim it during commissioning and walk-test from both the approach and the secure side before you sign off.
10) How long does the door stay unlocked after the MD-31D detects someone, and is the timing adjustable?
The MD-31D has a built-in relock time delay (RTD) that holds the release after detection and then re-engages the lock, so you are not depending on the access panel alone for that timing. If your job spec calls out a specific, field-settable delay range on the sensor itself, the Dortronics 6612 Series PIR is the one to look at instead, since it is listed with an adjustable 1 to 120 second time delay.
11) Can I standardize on the MD-31D across a hospital or school with a mix of header, wall and ceiling conditions?
That is the case for it. One model covers frame header, wall, and ceiling mounting, auto-senses 12 or 24VAC so it drops onto mixed panel voltages, and its coverage is set at the sensor by pointing the field rather than by ordering a different part per opening. For a facility carrying a spare parts bin, that means one sensor number and two finishes instead of a per-opening matrix.
12) Which request-to-exit motion sensor works in an unheated garage or an exterior vestibule?
The SDC MD-31D is rated for operation from minus 20 degrees F to 120 degrees F, which covers unconditioned parking structures, service corridors, and vestibules that see outside air. It also carries a compliance listing against IBC 1008.1.3.4, IFC 1008.1.3.4, NFPA 101 7.2.1.6.2, NFPA 1.15.5.3.2, BOCA 1017.4.5, and SBCCI 1012.7 for access-controlled egress doors, which is what an inspector will ask for on that opening. Among the request-to-exit alternatives, the Dortronics 6612 Series covers the same PIR detection function but on a 12/24VDC supply.
13) Which request-to-exit sensor has an adjustable time delay for how long the door stays unlocked?
The Dortronics 6612 Series carries an adjustable time delay settable from 1 to 120 seconds, which is the range to specify when a corridor or a loading area needs a long hold on the unlock. The SDC MD-31D handles timing through its relock time delay function, which controls re-engagement after the sensor detects an exit. If the job spec calls out a specific hold-open interval in seconds, the 6612 is the one with the published adjustment range.
14) The automatic door operator needs a sensor that keeps the swing path clear, not one that unlocks the door. Which one is that?
That is the LCN 8310 Series, specifically the 8310-804-1 door mount safety sensor with leading edge detection technology. It mounts on the door and monitors the leading edge as the door swings. The SDC MD-31D is a passive infrared request-to-exit detector for access-controlled egress doors, projecting a wraparound U pattern down and away from the door to detect a person approaching to exit, so it addresses code compliance for egress release rather than swing path protection.
15) What finishes does the SDC MD-31D come in, and will it disappear on a dark storefront header?
Two: matte black and matte white. Matte black is the usual pick on dark anodized aluminum storefront and on black-painted hollow metal frames; matte white suits painted drywall soffits and light ceilings on a ceiling-mount install. Both are the same sensor, so pick on the frame color, not on function.
How fast can I get the SDC MD-31DOW delivered?
Most orders ship the same day from our distribution partners, with quick delivery throughout the continental U.S. Need it urgently? Contact Us for expedited shipping options.
Can I return it if it doesn’t work for me?
Yes—ZenSupply offers a hassle-free return policy. If the product isn’t the right fit, reach out to our support team for a return authorization or setup a return by following our return instructions.
Does the SDC MD-31DOW come with a warranty?
Absolutely. The SDC MD-31DOW is backed by a manufacturer’s warranty. For full warranty terms, check the product documentation or Contact Us.
How do I get technical support or installation help for the SDC MD-31DOW?
You can call, text, or email our expert support team for fast answers. We’re here to help with product selection, installation tips, and troubleshooting. Contact Us
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