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 6,303 reports, 841 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

Hazardous & Explosion Proof Access Control Tutorial on Feb 27, 2020
Controlling access to hazardous environments requires equipment meeting specific ratings that certify they will not start fires or will not...
Breaking Into A Facility Using Canned Air Tested on Jan 28, 2020
Access control is supposed to make doors more secure, but a $5 can of compressed air may defeat it. With no special training, intruders can...
Multipoint Door Lock Tutorial on Jan 23, 2020
Despite widespread use, locked doors are notoriously weak at stopping entry, and thousands can be misspent on locks that leave doors quite...
Propped Doors Access Control Tutorial on Jan 07, 2020
Doors should keep 'bad guys' out, but a common access control problem is people propping doors open, preventing them from being secure. Even...
Glass Doors and Access Control Tutorial on Nov 21, 2019
One of the biggest access challenges are locking and securing glass doors. Unlike wood or steel doors that can be modified to work with...
Lock Status Monitoring Tutorial on Oct 28, 2019
Just because access doors are closed does not mean they are locked. Unless access systems are using lock status monitoring, the doors and areas...
Securing Access Control Installations Tutorial on Oct 17, 2019
The physical security of access control components is critical to ensuring that a facility is truly secure. Otherwise, the entire system can be...
Maglock Selection Guide on May 16, 2019
One of the most misunderstood yet valuable pieces of electrified hardware is the maglock. Few locks are stronger, but myths and confusion surround...
Access Control Request to Exit (RTE) Tutorial on May 13, 2019
For access controlled doors, especially those with maglocks, 'Request to Exit', or 'RTE' devices are required to override electrified locks to...
Door Closers Access Control Tutorial on May 02, 2019
Door Closers have an important job: automatically shut doors when they are opened, because an open door cannot control access. In this note, we...

Most Recent Industry Reports

VergeSense Presents People Tracking Sensor on Jun 04, 2020
VergeSense presented its people tracking sensor and social distancing insights at the May 2020 IPVM Startups show. A 30-minute video from...
FLIR A Series Temperature Screening Cameras Tested on Jun 04, 2020
FLIR is one of the biggest names in thermal and one of the most conservative. While rivals have marketed fever detection, FLIR has stuck to EST...
"Fever Camera" Show On-Demand Watch Now on Jun 03, 2020
IPVM has successfully completed the world's first "Fever Camera" show. Recordings from Both days are posted at the end of this report for on-demand...
Cobalt Robotics Presents Indoor Security and Access Robots on Jun 03, 2020
Cobalt Robotics presented indoor security robots at the May 2020 IPVM Startups show. Inside this report: A 30-minute video from Cobalt...
Dahua Sues Ex-North American President, Says Legal Typo on Jun 03, 2020
Dahua's former North American President Frank Zhang claims he is owed almost $11 million but Dahua counter claims it is just a "scrivener's error",...
Smart Entry Systems Presents Cloud Multi-Tenant Access Control on Jun 02, 2020
Smart Entry Systems presented Cloud Multi-Tenant Access Control at the May 2020 IPVM Startups show. Inside this report: A 30-minute video...
Genetec Drops Support for Dahua and Hikvision on Jun 01, 2020
Genetec has dropped support for Dahua and Hikvision, citing US blacklisting and ONVIF conformance blockage, the company informed partners in an...
Dotty "Hot Or Not" Elevated Body Temperature App Tested on Jun 01, 2020
What if you could take an existing phone or tablet and transform it into "fever camera"? That is what DottyAR is doing with their strangely named...
Optris "Fever Screening Systems" Examined on Jun 01, 2020
German manufacturer Optris has been building temperature measuring instruments for industrial manufacturing for over 15 years, and thermal cameras...
Fever Camera Sales From Integrators Surveyed on Jun 01, 2020
Fever cameras are the hottest trend in video surveillance currently but how much are integrators selling them? 220 integrators answered the...