Door Position Switches (DPS) For Access Control Tutorial

By Brian Rhodes, Published on Mar 05, 2018

Door position switches do not get enough respect. They solve a major problem of access control systems yet are frequently ignored or forgotten.

****** '*******' ****** ****** on ***** ******** ** make *** ***** ******* decisions ***** ******* ****** and ******* *****. ** this ****, ** **** at *** ** ***** the ***** *** ** contacts *** **** **** and ***** ***** *******:

  • ****** ********
  • *** **********
  • ****** ***** *********
  • ***** ****** *********
  • ****** ****** *****
  • ****** ****** ***** *********
  • ****** *******
  • ********** ********** ********
  • ********** ******** ********* *****

Door ******** ****** ******** ********

*** ****** *******, '**** position ********', **** ****** 'DPS', '**** ********', ** 'door *******', ****** ******* a **** ** ****** or ******.

********* *** ****** ******* system ********** ** **** interface ****** ** ***** this ****** ** *********. The ****** ** ******* is ******: **** * door ** ****, *** circuit ** ********. *******, when *** **** *****, the ******* ****** ****, signaling ** *** ****** system *** **** ** not ******. ***** ***** cannot ** ****** ** 'secured' **** ******, **** sensor ********* ***** * facility ** **** **********.

Security *********, *** ***** *******

****** ******* ******* *** blind ** ******* * door ** **** ** shut ******* ******** ********. Because **** ***** ****** limit ******** ** ******* unauthorized ****** **** ******** an ****, *** ** the ******* *** *** system '*****' ******* ** not * **** ** secure.

**** ********** ** *** install *** ** ***** to '**** *****' ** otherwise ******** *** ********, but **** ******** ** a ******** *******. ******* DPS, ****** ******* ****** be ******** '**********' ** all, *** ********** *** should ** * ********* aspect ** ***** *******.

Broad *********

******* **** ******** ******** are **** ** * variety ** *******, ***** are ********* ** ******* available. ***** ***** *********, there *** **** ** six ***** ***** **** in ********** ******:

**** ********** *** *** '********' ****** types ** ***** ********* and ******** **** ********* sporadic ***** ****** *** system ******* **** *****. Like ***** ****** **********, choosing *** ***** **** position ****** ******* ************* on *** **** - which **** ** **** it **, *** ***** it ** ****, *** even ***** ********* ** faces. ** ******* ***** factors ** ****** *****.

The ******* *******

***** ** *****, ****** selection ** ********* ***** on ***********, **** **** are ********* ** ***. Some ***** ** *** switches *** **** ********* to ******* **** ****** depending ** *** **** itself.

*** *******, ** * door ***** ** ********* into * ***** ******** or ******* ****, ******** enough ********* *** ******* wire ** * "*******" frame ***** **** ** difficult. *******, * "********" door ******* **** ****** be ***** ********* **** plane ***** ** ********* doors. ****** ***** ***** doors *** *** ****** be ******* ** *** "Recessed" *****, ****** *********** wood *****:

Mounting ********

*** **** ****** ** consider ** ***** *** sensor ****** ** *********. There *** * ****** of ******** ********* ** choose ****, ***** ** the ***** *****:

*** **** ** ******* once ***** ********** **** location. ***** **** *** physical **** ** ****, how ** ** **** and ***** *** ******* play * *** ****, including:

  • ********/********:**** **** ** ************* conditions ** *** ****** exposed **? ** ***-*********** office, ** ** ******* exposed ** ******* *******? 
  • ****/***/****:** *** ******* ** thresholds ****** *** **** fail, **** *** ****** be ******* ** ********, mud, ** *****?
  • ******* *******:*** ***** ** *** door ******? **** *** shift, ** * ******* times *** ****?

****** * ****** ** the **** *** ********* how ** ** **** help ****** *** **** sensor ****, ********** **** we ***** ** *** section *****:

Type *********

******** '******' *****:**** **** ** ****** is *** **** ******, usually ********* *** ***** ***** to ** ********* **** the *****, *** *** solid '******' ***** ***** installed **** * ******* hole ** *** ****. In **** ***** **** type ** ****** ** hung ** *** '*****' side, *** ** ******** during ************ ** *********/********* is *********.

  • ****: ****** '******' ******* are ********* *** ************* ******** in **** **********.  ************ is ****, ********* * minimum ** ******** *** wire *** **********.
  • ****: **** ***** ** alignment ******. *** ********* range *** ** **** precise, **** ******* ******* to ** ********* *********** adjacent ** **** *****. Vulnerable ** ***** ******, especially ** ***** *** buffeted ** **** ** vibrations.

******* *****:* **********, *** ********, style ** ******. **** the **** ** ****, the **** ******* * button, ********** *** *******. When *** **** *****, the ****** ** ********, signaling ** ****. ******* plungers *** **********, **** are *** ******* ** false ****** ****** ** wind ** *********. ********* plunger ***** *** ********* ** the ***** ****.

  • ****: **** *******, ******* lasting ******** ** ******. A '*** *****' ****** that ****** ********* ******. 
  • ****: ***** ** ******** because ** ****/*****. **** to ****** ** ****** with * **** ** screwdriver ****** ********* ** frame *** **** *********.

******* ***** *****:**** ** ******* ** most ***** ** *****: wood, ******** ******, *** hollow **** *****. ********* problems *** ******** ********* with ****** ****** ****.

  • ****: ****** *** ******* resistant ** ******** ************* effects (****/****/****/****). ******* ************ skill ********.
  • ****: ******* *** ******* to *********. *********** ************ in *************** ********* *****.

******** *****:* ***** ****-******* ******, very ****** ** **** frame ********** ***** ********. Generally **** *** **** is *****, ***** ** run ****** *** ***** side.

  • ****: *** ***** ** the ********* *************** ** plunger *****, *** ***** concealed.
  • ****: ********* **** ********* and **** ********* ** install **** ******* ******. Risk ** ******** **** or *** ****** ***** clearance ***** ** ********** until ****** ** ******* them.

******** ****:* ********* ****** ******** for ***** **** ******** 'up' ****** **** *****. Overhead/roll-up ***** *** ********* to ******* **** *********** sensors, *** ** **** and ******** ** ********** features.

  • ****: **** ** *******, and ********* ******** **** a *********** ******** *** armored ******* *** *****-**** use.
  • ****: ***** *********** ** false ****** *** ** wind *********. ********** ** dirt, *****, *** ******** damage.

Sensor *****

*** **** ** *** sensors ** ********* *****, with ************ ***** ******* higher **** *** ***** of *** ****** ******.  Most ***** *** ********* for ***** $**, **** only '**** ********' ** ruggedized ****** ***** **** expensive. 

System ********** ********

***** *** ********* ** *** ****** ******* **** ********** ** ** *****, ******* in *** *** ** contacts ************ ***** *** 'DPS' ** ** *** case ** *** *** **** *****, ** *** '**** Monitor' ********:

******* ***** ****** *** simple '******** ******' ******** and ***** ***** ** typically *** ****** ** the ********** *** *** use.

Sensor **** ********* *****

***** ** **** **** and ************ ********, ********** for ****** **** ********* are:

  • ********* *****: *** ******* ** ******** Magnetic ******, ********* ** 'drillability' ** ****.
  • ***** *****/**** ******: *** ******* ***** ** Recessed ****** ********* ** frame ********* *** **** frame ******** ****.
  • ******/********: *** ******* ** ******* Mount ******, ******* ******* is *** ******* ** issue *** ***** ************ ***** cost ****.

Common *********

***** *** *** ******* *******, however. **** ****** ** sidestep ********* *********** ****** by ****** ******** **** from *******, ******* **** manufacturers ******* *** **** practices ********* ***** ***. In *******, **** * sensor ******* * ****** of ***** ******, *** of *** ********* ********** is *** *******:

*****/****** ********:******** ** ********** ******* are ****** ** ******, dirt, ** ***** *** so **** ****** ******** break *******. * ****** rag *** ***** ******* wipe *** *** *** problem, *** ********* ******** may ******* ******** ***********.

************:***** *** ****** **** over ****, ******* ****** use. ********* *** **** shifts ****** **** ********** the **** ** ********** up *** ****** *** be ********.

******* ******:******* ******** *** ***** magnets ** ****** **** sensitive **** ****, *** greater ****** ** ******* corrosion ** **** ************ can *********** *** ****** life. *********** *** ** required **** ********** ** exposed ***** **** ******.

Magnetic ********* ****

***-********** ******* ********* *** magnets ** ***** ****/***** state. ******* ** **** magnetic ***********, **** ******* **** it ******** ** '****' the ****** **** ******* in * '****** *****' if * **** ********, stronger ****** ** ****** adjacent ** *** ******, even *** ******* ******** into ******.

****-******** ******* **** ************ *** ** **** ** place ** ******** *** to ****** ** ******* against *** *******, ** using **** ****** ********** ******* *** ***** **** magnetic ******* ********, ******** those ******* ********* **** 30% - **% **** than ************ *******.

[****: **** ******, ********** published ** ****, *** been ************* ******* ** 2018.]

Comments (11)

I agree they don't get enough respect, it still amazes me how many times we run into an installation with no door contacts, they provide critical information to an access control system.

REX's would be the next in line needing a little more respect, it's important to be able to differentiate between a valid exit and a door force.

You may just want to mention two other things:

While I understand not everyone works in secure detention facilities, there should be a passing mention how different (and big of a PITA) those kind of door switches can be.

It might also be good to point out why you would want to use a DPDT contact in certain circumstances.

I strongly agree to the recommendation that the use of DPS is the best practice inoder to monitor whether the door is open or closed.

There is no exaggeration in suggesting that DPS don't get enough respect as  i have just pointed out the missing DPS in the current on going installation. 

I just want to state that the knowledge acquired from IPVM is bearing the fruits. 

I agree with 

For Double Pole-Double Throw contacts, would those be useful in normally open (NO) circumstances?

Yes.  The double throw means it can be normally open or normally closed. If it were a double pull, single throw it would only be normally open or normally closed not both; although I don't think I've ever seen a door contact that is DPST.

The double pull means there are 2 independent circuits that can see the state change.  It's important to note that while both circuits are tied together and will see the same state change, they are independent when it comes to being normally open or normally closed.  Also because they are eclectically separate they can both have their own resistors in the circuits so one system can be NO with 1k Ohm in parallel and the other could be NC with 100 Ohm in series.

You guys mean double-pole, not poll or pull, right? :)

Yes, double pole is correct.  I'm not sure why I wrote 'pull' or if it autocorrected to that, but I've changed it now.

 I can't edit mine for some reason.

I disagree about the “Magnetic 'Bullet' Style” being hard to align. We use these 90% of the time (we do a lot of access control) and we don’t find this to be a issue.

It is not difficult if you install them regularly, like yourself, or if you have experience recessing door contacts in intrusion work, but for a novice getting the top and bottom halves lined up can be tough. 

Also, making basic alignment measurements can be a challenge if the door itself is out of square or unaligned with the frame.  

Read this IPVM report for free.

This article is part of IPVM's 6,596 reports, 889 tests and is only available to members. To get a one-time preview of our work, enter your work email to access the full article.

Already a member? Login here | Join now

Related Reports

Forced Door Alarms For Access Control Tutorial on Aug 17, 2020
One of the most important access control alarms is also often ignored....
Door Fundamentals For Access Control Guide on Aug 24, 2020
Doors vary greatly in how difficult and costly it is to add electronic access...
Exit Devices For Access Control Tutorial on Aug 25, 2020
Exit Devices, also called 'Panic Bars' or 'Crash Bars' are required by safety...
Access Control Levels and Schedules Tutorial on Sep 29, 2020
Configuring access levels and setting up schedules is central to maintaining...
Drain Wire For Access Control Reader Tutorial on Sep 23, 2020
An easy-to-miss cabling specification plays a key role in access control, yet...
Keypads For Access Control Tutorial on Jul 28, 2020
Keypad readers present huge risks to even the best access systems. If...
AHJ / Authority Having Jurisdiction Tutorial on Aug 06, 2020
One of the most powerful yet often underappreciated characters in all...
FLIR Markets Windows Temperature Screening, Violates IEC And Causes Performance Problems on Jul 17, 2020
FLIR, one of the largest thermal screening manufacturers, is marketing...
Uniview Deep Learning Camera Tested on Jul 14, 2020
Uniview's intrusion analytics have performed poorly in our shootouts. Now,...
Ubiquiti Access Control Tested on Oct 21, 2020
Ubiquiti has become one of the most widely used wireless and switch providers...
Monitoring Alarm Systems From Home - Innovation or Danger? on Oct 13, 2020
Remote monitoring by alarm companies since COVID-19 is bringing cost savings...
Face Masks Increase Face Recognition Errors Says NIST on Aug 04, 2020
COVID-19 has led to widespread facemask use, which as IPVM testing has shown...
Faulty Hikvision Fever Cam Setup at Mexico City Basilica and Cathedral on Oct 14, 2020
Donated Hikvision fever cameras (claiming screening of 1,800 people/min. with...
Top Video Surveillance Service Call Problems 2020 on Oct 23, 2020
3 primary and 4 secondary issues stood out as causing the most problems when...
The Insecure Verkada Access Control System on Jun 25, 2020
While Verkada touts the security of its system and that how their new door...

Recent Reports

VICE Investigates Verkada's Harassing "RawVerkadawgz" on Oct 26, 2020
This month, IPVM investigated Verkada's sexism, discrimination, and cultural...
Six Flags' FDA Violating Outdoor Dahua Fever Cameras on Oct 26, 2020
As Six Flags scrambled to reopen parks amid plummeting revenues caused by the...
ISC Brasil Digital Experience 2020 Report on Oct 23, 2020
ISC Brasil 2020 rebranded itself to ISC Digital Experience and, like its...
Top Video Surveillance Service Call Problems 2020 on Oct 23, 2020
3 primary and 4 secondary issues stood out as causing the most problems when...
GDPR Impact On Temperature / Fever Screening Explained on Oct 22, 2020
What impact does GDPR have on temperature screening? Do you risk a GDPR fine...
Security And Safety Things (S&ST) Tested on Oct 22, 2020
S&ST, a Bosch spinout, is spending tens of millions of dollars aiming to...
Nokia Fever Screening Claims To "Advance Fight Against COVID-19" on Oct 22, 2020
First IBM, then briefly Clorox, and now Nokia becomes the latest Fortune 500...
Deceptive Meridian Temperature Tablets Endanger Public Safety on Oct 21, 2020
IPVM's testing of and investigation into Meridian Kiosk's temperature...
Honeywell 30 Series and Vivotek NVRs Tested on Oct 21, 2020
The NDAA ban has driven many users to look for low-cost NVRs not made by...
Ubiquiti Access Control Tested on Oct 21, 2020
Ubiquiti has become one of the most widely used wireless and switch providers...
Avigilon Aggressive Trade-In Program Takes Aim At Competitors on Oct 20, 2020
Avigilon has launched one of the most aggressive trade-in programs the video...
Mexico Video Surveillance Market Overview 2020 on Oct 20, 2020
Despite being neighbors, there are key differences between the U.S. and...
Dahua Revenue Grows But Profits Down, Cause Unclear on Oct 20, 2020
While Dahua's overall revenue was up more than 12% in Q3 2020, a significant...
Illegal Hikvision Fever Screening Touted In Australia, Government Investigating, Temperature References Deleted on Oct 20, 2020
The Australian government told IPVM that they are investigating a Hikvision...
Panasonic Presents i-PRO Cameras and Video Analytics on Oct 19, 2020
Panasonic i-PRO presented its X-Series cameras and AI video analytics at the...