******* ****** *** ********** monitor *** ****** ** attached ********, *******, *** devices ** ****** **** they ****** ***********. **** is ***** ** ***********. Poor ************** ** *********** is * ****** ****** of ***** ******. *******, if ******** *********, *********** can ******** ***** **** the ***** ******* **********, and *** ***** ********** to ********* ********, ******** them ** ****** ****. In **** ****, ** examine ***** ***********, *********
- **** ** * ********** circuit?
- ********** ** ************ ********
- ******* *** ***** **********
- ***** *********
- ***** ** ******* *** resistor
- ******* *******
- ************** **********
- ***** ***** ***********
What ** * ********** *******?
**************** ******* ** ****** is *** **** ** constantly *** ******** ******* by *** ***** ***** to ****** **** ** is ***** ********** *** responsive. ** **** **** by ******* *** ********** on *** *******, *** comparing ** ******* * selected *****.
Alarm ***********: *** *** ***
***** *** **** ******* to *** ***** ***********, including:
- **** ********* ******* ***********
- ******* ** *** ** higher ****** ***** ****, such ** ** ****** alarms (******* ******, *****, etc)
- ********** **** ****** ****** require ***********
- ******* ** ******** ********** accounts
- ********** ****** *** *** alarm ********* **** **** alarm ** *********
- ** ***** ** ************, customer *** ** ******* on ****** ***** ** protect ********
**** ***** ********* ***** use ***********, ** **** use *********** *** ********** applications *** *** *********** ones. *** ******* *******:
[***************]
- ****** ******* **** ********* takes ****** *** ** more *********
- ******** ******** **** ***** in ********* *** ********* and **** ** *******-*******
- ************ *********** ******** ****** trained ***********
- ** * ********* **** is *** ******** ***** away, ***** *********** *** become *****
*********** ***** ************* *** quickly ****** ************ ****** they *** ** ********* quickly *** ***********, *** highly ******* ***** ********** who ********** *** ** implement *********** ******* ****** salaries **** **** *** do ***. *******, *** main ********* ** *********** is ** ****** **** the ***** ** ********** functional *** ******* ** protecting *** ******** ** which ** *** **** installed. *** **** ******, it ** ****** *********** that *********** ** **** in ***** ****.
Supervised ** ************ ********
** * ********** ******* opens, *** ********** **** go **** *** ********, causing *** ***** ** go **** ***** *********. However, ** *** ********** reading ************ ******** *** ** a *****, *** ***** goes *********** *********.
** ********, ************ ***** simply **** *** * closed *******, ***** **** alarm ********* **** ** the ******* *****.
** ********* *****, **** means **** **** *** circuit ** ************, *** panel ****** **** *** difference ******* * ****** sensor *** * ******* wire. *********, * ****** adversary *** ******* ** shunt * ****** ** shorting *** **** ******* to *** ******. **** 'blinds' *** ***** ***** and ****** *** ********* to **** *** ***** the ****** ******* ******* off *** *****.
*** ********* ***** ************ how * ********** **** works.
Getting *** ***** **********
*** ********** ******** ** create * ********** ******* is ********* ** *** manufacturer. *** *******, ********* panels ******* **Ω (*,*** ohms), ***** ******** *.**Ω, and *** ******** **Ω. Because *********** ** ********* on *** ********** ***** within * ******** *****, installers *** * ****** called *********** ****** *** ********** is *******.* ******** ** * device **** **** * specific *** ********** ****** of ********** ** * circuit. * ******** ** a ******* ******, ***** means ** ****** ** adjusted ** ********** *** does *** *** ** output *******. **** ************* include * **** ** resistors **** ***** ***** panel ****. ********** ******** are ******** ******* *.**Ω and *.**Ω.
*******-**** ********* **** **** long, ******** *****, ** opposed ** *******-***** *********, which *** ******** ** be ******** **** * PC *****. **** ****** alarm ********** ** **** the ******** ****** *** end ** *** *******, thus ****** *** ****** circuit * *****, ******** resistance *****. **** *** alarm ***** ***** *** circuit, ** **** **** all *** ********** *********** by *** ****, *******, and *******, **** *** resistor.
********* **** ** ****** are ******** ** ********* (k) ** **** (Ω). For *******, * ******** that **** *,*** **** to * ******* ** known ** * **Ω resistor. * ******** **** adds *,*** **** ** a ******* ** ***** as * *.**Ω ********.
*** ********* **** ***** bands ** **** **** they *** ***** ***. The **** ****** ****** is **** *****. *** the ****** ********** ** specific *******. *** ***** two ***** ******** *** rating ** ******, ***** are **** ********** ** the ***** ****. *** example *** ******** ** the ***** *** * red ****, ******* *, a ***** ****, ******* 0, ****** ** **, and * *** ****, telling ** ** ******** the ****** *****, ****** it * ***Ω ********. The ***** **** ********* the ********* ** *** resistor. **** **** ** gold, ***** ********* * tolerance ** ±*%. ********* are ******** **** ** variety *****, ***** ******* labels, ** ******* ***** resistor ** *** **** is *** ******* *** is ****** ** ****. Resistors *** ** ********* from ***** ***** *** electronics ****** ******.
Using *********
*** ***** ********** ******** for *********** ******* **** manufacturer ** ************. ***** panel ************* ******** ******* their ***** ****** **** resistors. ********* ***** ************* require ********* ******** ******, so ***** ********* **** have * **** ** installed ****** **** ******** manufacturers *** **** ** keep * *** ** hand *** ******* *****.
**** ****** **** * feature ********** ********. **** ***** **** doubling, ** ********* *** run *** ***** ** wires ** * ****** set ** ********* ** the ***** *****. ** the *** ** **** pair ** ***** **** be * ********* ***** resistor. *** ***** *** identify *** **** ****** based ** *** **** of ********** ****.
Where ** ******* *** ********
********* ****** ****** ** on *** ***** ** the ******* **** ** the ******** **** *** panel. **** ** ***** as*** *** ** *** line. **** ***** ***** manufacturers ***** ** ********* used **** *** ** end ** **** *********, or *****.
*** **** ****** *********** method ******** ********** *** resistor ** *** ** the ********* ** * sensor ** ******. **** is ************ ********* ** there ** * ****** device ** *** ****, and ** ***** ** room ****** *** ****** for * ********. *** example, * ********** ** motion ******** *** ****** accommodate * ********, *** these ******* *** ***** wired ** ***** *** zone.
******** ******** *** ***** wired ** ****** **** other ********. *** *******, if ***** *** ******* windows **** ** **** other, ** ********* *** choose ** **** *** the ******** ********, ** that *** *** ******* share *** **** ****. In ***** *****, *** resistor **** ** ** the *** ** *** line, ***** ** ** say, *** ***** ** the **** ******** **** the *****.
**** ******* ***** ******** contacts **** ******** ****** that *** *********** * resistor. *** ******* ********, which *** ***** *** unobtrusive, ** *** **** with ******** ****** *** cannot **** * ********. Installing * ******** ** a ***** ***** ******** contact ** **** ******* can ** ***** *********** as ****. ** ********** an *** ** **** resistor **** ** *********, an ********* *** ****** to *** *** **** wire ******, ***** ****** the ******** ** ** installed ** *** ***** instead ** ** *** field (** ** *** sensor ** ******).
******** ******** **** *****-** resistors *** **** ********* to ******** **** ******* manufacturers **** ** *** and **********. ******* ** the ********** ************ ****** from ************ ** ************, these ********* *** ***** not ******* ** ***** suppliers *** **** ******* be ******* *******. **** the ******* ******** **** the ***** *** **** a *****-** ********. ***** more **** *** ******** on * *******, ** putting *** ******** ** the ***** ****, **** prevent *** ***** ***** from *********** *** *******.
Insider *******
******* ******, ** ***** nature, ******* ********** **** threats ** *** ******* of *** ********* ****. However, ** ** **** difficult ** ******* ******* threats ** *** ****** of *** ********* ****, especially ** ***** ******* can ****** *** ********* while *** ***** ** disarmed. ********* *** **** to ***** ** ****** in * ***** **** their ********* **** ****** of **** *** *********** to ***** *** ******* alarm, ******** *** **** spots, *** ******** ** disable *** ***** ** that ** **** ** unable ** ****** * break-in ***** *****. ***** supervision ** *** *** alarm ********** ****** ******* these ******* *******.
** ** ******** ****** a **** ** "*****" a ******* ****** *** day, ********* ** **** back *** ****** *** place ** *****, *** alarm **** **** * trouble ****** ** *** keypad, ****** * *********** party *** *********** ** investigate *** ***** *** source ** *** *******.
Implementation **********
*********** **** ** ***** step ** ****** ******, and ********* *** ** tricky ** **** ****. It ** ***** ********* to *** ********* ** low ******* ******** ******** and ***** ***** ********. Magnetic ******** **** ***** in ********* *** *********, but **** *** **** expensive **** ******** ********. However, *** ******* ********* is *********** *****, *******, the *** ** *** line ******** **, ********** when ****** **** *****. Determining *** ******** ***** requires ****** *********** ***** wiring ** ********* ********** with * ***** ***** the ****.
*** **** ****** ****** of ********* ** *** exact ********* ** *** resistor. ********* **** ** placed ** *** ******** point ** *** ****, which ** ** *** device. ** **** ** placed ****** *** ********, not ****. ** * resistor ** ****** ****** the *** ** *** wire, ******** ******* **** will ** ************, *** if * ******** ** placed ****** *** ********* of *** **** ******, it **** ******* *** zone **** *******.
Comments (13)
Marty Calhoun
The picture on the right is mistakenly labeled 'incorrect'. If this is an "Open Circuit device" such as Foot pedal, Money clip, etc. it is in the right place. Secondly, not often but it has happened, manufacturers will label a device as to the condition of the relay when activated, therefore this is correct as well.
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Undisclosed Integrator #1
Most modern powered detection devices with "NC" and "C" are closed loop (or Normally Closed), so in that case it would be incorrect.
The picture with same device where resistor is properly placed, I would have incorporated the tamper:
green on 1st "T", one leg of resister on 2nd "T", other leg of resistor on "C" and white on "NC"
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Undisclosed Distributor #2
Here we often use double end of line (DEOL) to allow for both alarm & tamper conditions on a single pair. It allows tamper monitoring 24/7 for both sensor housing & cable tamper along with alarm monitoring only when system is armed
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Michael Silva
Another great article, Ari!
You have touched upon one of pet gripes: the failure of installers to place EOL resistors where they belong - at the end of the line. I just completed a survey of 32 commercial sites that had intrusion alarm systems installed by a variety of alarm companies. In nearly every case, the resistors were at the panel. The exception was a multiplexed system that used zone expanders out in the field. In this case, the resistors were at the zone expander, not at the device. Same problem.
I consider this practice to be negligence on the part of the installer. In jobs we specify, we always verify that EOL resistors are properly installed and will make the installer rework the job if it isn't right.
Looking for your article on tamper switches, another one of my pet peeves. I did a short article on the topic myself a short time back.
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Undisclosed #3
Say it isn't so :)
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