EOL RESISTORS
lrl...@mindspring.com
Had a problem with a Vista 20. Supplied EOL resistors were 2.7K. Specs
say 2.0K maximum loop resistanance + I think 300 ohms. Replaced with
2.0K ohm and cleared problem. Question to settle dissenting opinion is
should EOL be in series with contacts on parallel? I say in parallel
so panel see's either 2.0k or short. Another insists in series with
contacts so as to see open or 2.0k minimum loop resistance. What does
the jury sayeth? Thanks!!
Robert L Bass
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lrl...@mindspring.com wrote:
If the EOLR is in parallel with a contact that closes on alarm on, say, a
door the circuit will detect the following conditions:
SHORT - The door is open. When disarmed this is OK. When armed the system
will go into alarm.
OPEN - The wire has been cut. When disarmed the system will show "DAY
TROUBLE" and the keypads will sound a warning. The system may also be
programmed to report the condition to the C-Station. When armed the system
will go into alarm.
EOLR - The door is closed and the circuit is normal. No explanation
needed.
If the EOLR is wired in series with a contact that opens on alarm on the
same door, the circuit will be able to give the following indications:
OPEN - The door is open *or* the wire has been cut. If the system is
disarmed it will just look like a door is open. No trouble is indicated
until the client tries to arm at the end of the day.
EOLR - Same as when the other wiring technique is chosen.
I hope this helps you decide which course you wish to follow. BTW, you
can order contacts with built-in (read: hidden) EOL resistors from Sentrol
(not to be confused with Sonitrol), among others. The advantage with
these is there's no visible connection point to defeat the EOLR. If you
ever change to a totally different control panel years later, you *may*
need to pull out the contacts and replace them. If it's a commercial job
and the contacts are surface mounted, this is a snap. Two minutes per
contact with a screwdriver and voila! If the contacts are recessed (like
the 1275W) you'll have to pull them out, but this really isn't that hard.
It adds a couply of extra minutes per contact though.
Regards,
RLBass
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VSS DOUG
Irlisle wrote
>Question to settle dissenting opinion is
>should EOL be in series with contacts on parallel? I say in parallel
>so panel see's either 2.0k or short. Another insists in series with
>contacts so as to see open or 2.0k minimum loop resistance. What does
>the jury sayeth? Thanks!!
>
>
It depends on the type of circuit/loop and sensor used.
If the sensor opens the circuit/ loop on alarm then the EOL resistor would
normally be connected in series with the sensor.
If the sensor closes the circuit/ loop on alarm then the EOL resistor would
normally be connected in parallel across the last sensor in the circuit/ loop.
Doug L
Dualtec1
Why oh why do Scantronic insist on having only two resistors per EOL cct on a
multiple device cct . ie 2 or more contacts.
This is okay if they are next to each other like a double leaf door but if the
zones are spread over a site it`s a nightmare having to carry a third wire
across to enable the shunt resistor to go across all ccts.
This in my opinion is not neccesary........Scantronic please follow the example
of your competitors and use multiple shunt resistors, not only does this make
it easier to install but easier to fault find too.
Anyone agree/disagree.............Speak now or keep quiet!
Doug Winslow
lrl...@mindspring.com wrote:
>
> Had a problem with a Vista 20. Supplied EOL resistors were 2.7K. Specs
> say 2.0K maximum loop resistanance + I think 300 ohms. Replaced with
> should EOL be in series with contacts on parallel? I say in parallel
> so panel see's either 2.0k or short. Another insists in series with
> contacts so as to see open or 2.0k minimum loop resistance. What does
> the jury sayeth? Thanks!!
I read RLBass' response and it is technically correct for the most part.
The part he forgot is that it depends on what the control set "demands".
Some don't care while others do... Doug
Doug Winslow
Doug, if you'd really read the first part of the post you wouldn't have
wasted our time with your post. Doug
Fred Long
First question is, did you measure the loop resistance to see if it was
out of tolerance? Most security alarms today work on both normally open
contacts and normally closed contacts. The end of line resistor will be
placed at the end of the circuit so the panel will see that resistance
in a normally open application or that resistance and the normal loop
resistance in a normally closed app.
My belief is to use a normally closed circuit with an EOL resistor in
parallel, panel is programmed for a trouble on an open or short when
unarmed, a delayed alarm on an open when armed and an instantaneous
alarm if shorted when armed.
I would venture a guess that your system was wired for normally closed
contacts wired in series with the EOL resistor. Your loop resistance,
the contacts and wire resistance, was greater than the 2.0K + the 300
ohms and when you replaced the EOL with a smaller vallue the loop
dorpped to within tolerance.
Fred Long
First question is, did you measure the loop resistance to see if it was
out of tolerance? Most security alarms today work on both normally open
contacts and normally closed contacts. The end of line resistor will be
placed at the end of the circuit so the panel will see that resistance
in a normally open application or that resistance and the normal loop
resistance in a normally closed app.
My belief is to use a normally closed circuit with an EOL resistor in
parallel, panel is programmed for a trouble on an open or short when
unarmed, a delayed alarm on an open when armed and an instantaneous
alarm if shorted when armed.
I would venture a guess that your system was wired for normally closed
contacts wired in series with the EOL resistor. Your loop resistance,
the contacts and wire resistance, was greater than the 2.0K + the 300
ohms and when you replaced the EOL with a smaller vallue the loop
dorpped to within tolerance.
Comments Welcome
Fred Long
fred...@inreach.com
RABSparks
Doug L's right on the money.
Robert L Bass
Doug Winslow wrote:
>
> Doug Winslow wrote:
> >
> > lrl...@mindspring.com wrote:
> > >
> > > Had a problem with a Vista 20. Supplied EOL resistors were 2.7K. Specs
> > > say 2.0K maximum loop resistanance + I think 300 ohms. Replaced with
> > > 2.0K ohm and cleared problem. Question to settle dissenting opinion is
> > > should EOL be in series with contacts on parallel? I say in parallel
> > > so panel see's either 2.0k or short. Another insists in series with
> > > contacts so as to see open or 2.0k minimum loop resistance. What does
> > > the jury sayeth? Thanks!!
> >
> > The part he forgot is that it depends on what the control set "demands".
> > Some don't care while others do... Doug
>
> Doug, if you'd really read the first part of the post you wouldn't have
> wasted our time with your post. Doug
Huh??? Which part of my post did not apply to the installation in
question. The gentleman is using a Vista 20. The information in my post
was not just "mostly" correct. It was precisely correct. Also, if the
panel is capable of differentiating between a trouble (open) and an
alarm (short) the EOLR should indeed be wired in parallel to a contact
that closes on alarm. If the panel can not so differentiate, then first
there's no reason to bother with the EOLR, and second, the panel is a
cheapy that should be discarded in favor of something better.
This doesn't mean that an EOLR is always required. But any UL listed
panel can tell the difference between an open and a short. The best
panels allow you to assign open or short as alarm or trouble and vice
versa. Consider the Napco Gemini series, for example.
Regards,
RLBass
Fightcrime
lrl...@mindspring.com wrote:
>Had a problem with a Vista 20. Supplied EOL resistors were 2.7K. Specs
>say 2.0K maximum loop resistanance + I think 300 ohms. Replaced with
>2.0K ohm and cleared problem. Question to settle dissenting opinion is
>should EOL be in series with contacts on parallel? I say in parallel
>so panel see's either 2.0k or short. Another insists in series with
>contacts so as to see open or 2.0k minimum loop resistance. What does
>the jury sayeth? Thanks!!
EOL resistors go in series with the last device on the loop/zone. This provides
EOL resistance under normal conditions, open when door/window or device
activates and a short if there is a pinched or shorted wire, a short and a open
will normally cause an alarm condition at the panel if armed.
The alarm installation manual or wiring diagram in the panel should have
indicated by a picture that the EOL resistor is to go in series on the
loop/zone.
David J. Rosso
Affordable Home Security Systems
--------------------------------------------------
http://members.aol.com/fightcrime
TONY1011
>STORS
>From: Doug Winslow <do...@min.net>
>Date: Mon, Nov 24, 1997 21:42 EST
>Message-id: <347A3B33...@min.net>>> >Snip
I do Tech Support for Ademco, I get alot of calls concening EOLR's. It seems
that there is alot confusion. First if the contacts are N.O. (Fire loop) then
the EOLR must be in Parallel. If the loop is N.C. (door/window) then it should
be in series. And remember, if its a fire loop the EOLR MUST be in parallel.
Hope this helps..
Tony
Ademco Tech Support
Robert L Bass
Fightcrime wrote:
>
> lrl...@mindspring.com wrote:
>
> >Had a problem with a Vista 20. Supplied EOL resistors were 2.7K. Specs
> >say 2.0K maximum loop resistanance + I think 300 ohms. Replaced with
> >2.0K ohm and cleared problem. Question to settle dissenting opinion is
> >should EOL be in series with contacts on parallel? I say in parallel
> >so panel see's either 2.0k or short. Another insists in series with
> >contacts so as to see open or 2.0k minimum loop resistance. What does
> >the jury sayeth? Thanks!!
>
> EOL resistors go in series with the last device on the loop/zone. This provides
> EOL resistance under normal conditions, open when door/window or device
> activates and a short if there is a pinched or shorted wire, a short and a open
> will normally cause an alarm condition at the panel if armed.
>
> The alarm installation manual or wiring diagram in the panel should have
> indicated by a picture that the EOL resistor is to go in series on the
> loop/zone.
The manuals almost always show the use of the EOLR in multiple possible
configurations. However, the method I have outlined will always provide
the maximum level of protection and supervision for the circuit.
Placing the EOLR in series with, but outside of the contact leaves the
contact exposed to easy circumvention. My method will effectively
protect against this. Since the main use of EOLR in many locations is
to protect against tampering by persons who are lawfully on premises
during the disarmed state (for example, employees at a store), it is
important NOT to wire a separate EOLR in series with the contact.
Blue Skies,
RLBass
Robert L Bass
TONY1011 wrote:
> .... I get alot of calls concening EOLR's. It seems
> that there is alot confusion. First if the contacts are N.O. (Fire loop) then
> the EOLR must be in Parallel. If the loop is N.C. (door/window) then it should
> be in series. And remember, if its a fire loop the EOLR MUST be in parallel.
*UNLESS* the contact has an integral EOLR. In that case, the
door/window can and should be N.O. (short = alarm, open = trouble, EOL =
secure).
RLBass
Lewis Lisle
lrl...@mindspring.com wrote:
Replacing the 2.7k ohm resistors with 2.0k did take care of the
problem. Apparently we were just out of tolerence. Thanks for all the
feedback. Maybe next time something more exciting like "two wire
hookup, three wire screwup". Happy Holidays to all!!!!!
Doug Winslow
> > > I read RLBass' response and it is technically correct for the most part.
> > > The part he forgot is that it depends on what the control set "demands".
> > > Some don't care while others do... Doug
> >
> > Doug, if you'd really read the first part of the post you wouldn't have
> > wasted our time with your post. Doug
>
> Huh??? Which part of my post did not apply to the installation in
> question. The gentleman is using a Vista 20.
Re-read my response and most importantly my flame to myself for not
reading the first line closer when I made the first reply. You were
accurate in your reple to him. Doug
8420847...@tx.netcomm.com
(short = alarm, open = trouble, EOL =secure).
from "EOL" to "open" for a burg zone when armed? (i.e. is an open a trouble or alarm
condition when armed ) On a N.O. Fire loop open is always a trouble but on a N.O.
burg loop open is a trouble when not armed and alarm when armed in case of
intentional cutting of the circuit wire. From what I can tell using the N.O. loop
for burg zones provides improved or additional "DAY" supervision of the loop only.
You always know that the loop is in working order even if the loop is for example on
a door that is propped open during the day when the system is not armed. Whereas in
the above example you cannot get the same level of supervision on a N.C. loop even
with "Day Zone" trouble annunciation or reporting.
robertde
If the contacts open during alarm....connect the EOL in series.
If the contacts close during alarm...then parallel EOL is correct.
lrl...@mindspring.com wrote in article
<65b539$8...@camel21.mindspring.com>...
Robert L Bass
Someone wrote:
>
> (short = alarm, open = trouble, EOL =secure).
> Understood, but what type of report code do you use (send) on this circuit if it goes
> from "EOL" to "open" for a burg zone when armed? (i.e. is an open a trouble or alarm
> condition when armed ) On a N.O. Fire loop open is always a trouble but on a N.O.
> burg loop open is a trouble when not armed and alarm when armed in case of
> intentional cutting of the circuit wire. From what I can tell using the N.O. loop
> for burg zones provides improved or additional "DAY" supervision of the loop only.
> You always know that the loop is in working order even if the loop is for example on
> a door that is propped open during the day when the system is not armed. Whereas in
> the above example you cannot get the same level of supervision on a N.C. loop even
> with "Day Zone" trouble annunciation or reporting.
This is correct. The day (disarmed) supervision is only available with
the N.O. device wired in parallel to the EOLR. This is why I always use
this method for any EOLR supervised loops. Also, since the internal
(built-in) EOLR is virtually impossible to defeat without specific prior
knowledge, it renders the highest possible security.
The limited supervision available using an outboard resistor in series
or in parallel is quite easily circumvented. Complaints that this
method makes it harder to upgrade later are really only objections to
possible extra work at some future date. If the question is, "How do I
best protect this building against unlawful entry," then this is a
non-issue. In any case, if you find a reliable manufacturer and stick
with them you will not often face the need to make major changes. Any
1K-Ohm supervised circuits that I have installed over the last 18 years
will work fine with about 80% of the products on the market. A large
part of the remaining manufacturers use a 2.2K-Ohm resistor. This
leaves a lot of flexibility if I ever wish to change. Finally, if you
take the trouble to leave a 12" "service loop" of extra wire inside the
wall behind each buried contact it is a fairly quick job to pull out an
old sensor, splice in a new one and re-insert it.
I like using Napco's Gemini and MA-3000 series panels partly because
they facilitate this so well. The Napco panels allow me to specify for
each individual zone if it will report at all, how it will report an
open or a short while armed and while disarmed. I can thus supervise
virtually anything at just the level I need.
Blue Skies,
RLBass
Robert L Bass
Oh, yes. Peace and Tranquility Mode: ON :)
Blue Skies,
RLBass
Flyboy
Robert L Bass wrote:
> this method for any EOLR supervised loops. Also, since the internal
> (built-in) EOLR is virtually impossible to defeat without specific
> prior
> knowledge, it renders the highest possible security.
Slightly off subject, but the above "specific prior knowledge" would be
a voltmeter and Ohms Law. Both common knowledge therefor not very
difficult to defeat.
--
Tom and Sandra Brown Hyak Ski Patrol
Olympic Security and Communications Systems NSPS #P008-67286
GSX1100G VS700 KLR600 KLR250
Remove the "no.spam." from address to reply.
Warren
If you were playing with a Software House APC panel, you would have the
added fun of using 2 resistors, one in series and the other in parallel.
-------------\-/\/\/\/\-----
. / Normally Open
Panel \ Normal state - Panel sees 1000 Ohms (1K)
. / Alarm state - Panel sees 500 Ohms
-------------\--------------
----\/\/\/\/-\--------------
. / Normally Closed
Panel \ Normal state - Panel sees 1000 Ohms (1K)
. / Alarm state - Panel sees 2000 Ohms (2K)
-------------\--------------
lrl...@mindspring.com wrote:
>
> Had a problem with a Vista 20. Supplied EOL resistors were 2.7K. Specs
> say 2.0K maximum loop resistanance + I think 300 ohms. Replaced with
> 2.0K ohm and cleared problem. Question to settle dissenting opinion is
> should EOL be in series with contacts on parallel? I say in parallel
> so panel see's either 2.0k or short. Another insists in series with
> contacts so as to see open or 2.0k minimum loop resistance. What does
> the jury sayeth? Thanks!!
--
Warren's Turkey Hunting Home Page | "Jane, stop this crazy thing!!!"
http://www.access.digex.net/~geeisee | My New Years resolution
mailto:gee...@bigfoot.com | 1024 X 768
Robert L Bass
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Flyboy wrote:
>
> Robert L Bass wrote:
>
>> this method for any EOLR supervised loops. Also, since the internal
>> (built-in) EOLR is virtually impossible to defeat without specific
>> prior knowledge, it renders the highest possible security.
>
> Slightly off subject, but the above "specific prior knowledge" would be
> a voltmeter and Ohms Law. Both common knowledge therefor not very
> difficult to defeat.
REALITY CHECK: Most thieves don't use any tools more technical than a
pry bar or a large screw-driver. The dishonest employee looking to beat
the 7 Eleven out of a few cases of Coors and Marlboros by coming back
after hours is usually, after all, a 7 Eleven clerk. Voltmeter?
Maybe. Ohm's law? Naaah. But they usually can short out a couple of
screw terminals on the 1285-T mounted on top of the side door to the
store before leaving for the night. If they do this with the type I use
it won't arm. And if they tamper during store hours, we call the owner.
The business of protecting ordinary property, such as residential and
light commercial structures, is not that complicated an affair. A few
added twists, like a concealed EOLR in a contact greatly improve the
level of protection. To make it truly impenetrable would require a much
greater investment than is merited by the risk factor. That doesn't
make the effort and the extra $2-3 for a supervised contact a waste.
You do what you reasonably can be expected to do to provide a level of
protection consistent with the threat and the possible consequences of a
loss.
Blue Skies,
RLBass
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Irv Fisher
On Sun, 30 Nov 1997 21:52:26 -0500, Robert L Bass
<alar...@BassHome.com> wrote:
>REALITY CHECK: Most thieves don't use any tools more technical than a
>pry bar or a large screw-driver. The dishonest employee looking to beat
>the 7 Eleven out of a few cases of Coors and Marlboros by coming back
>after hours is usually, after all, a 7 Eleven clerk. Voltmeter?
Had a nice hit this week gentlemen on a record store.. Loss >$80K in
CD's. Digital control, mounted high up in t-bar, not likely to be
seen by a prybar kind of guy. Motions only. No contacts. Entry is
through a rear door forced open. Wiring at control panel all cut.
Wall to wall loss. Sure looks inside to me. Thought the siren might
have drawn the bandit to the control but it never went off. We got
the closing on time. Might have hid inside -- might not.