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FIRE SERVICE AND GENERAL FIRE SAFETY TOPICS => Technical Advice => Topic started by: Benzerari on November 24, 2008, 06:16:35 PM
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Imagine 30 devices missing in a loop that has a short circuit, when opened one of the missing call points, I found in one end short circuit and the other end 24Vdc, I connected back the call point with the legs of 24Vdc, and left the other legs of short circuit disconnected.
In here started some other weird things, the 30 devices missing came back perfectly, but I lost another 30 devices, also some of the devices show states 'normal' but with analogue value '0', also some other detectors shown as missing but their analogue value '23'.
It can't be the loop card as it was flashing just like other three loop cards, what else could be the problem?
Any suggestions?
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Imagine 30 devices missing in a loop that has a short circuit, when opened one of the missing call points, I found in one end short circuit and the other end 24Vdc, I connected back the call point with the legs of 24Vdc, and left the other legs of short circuit disconnected.
In here started some other weird things, the 30 devices missing came back perfectly, but I lost another 30 devices, also some of the devices show states 'normal' but with analogue value '0', also some other detectors shown as missing but their analogue value '23'.
It can't be the loop card as it was flashing just like other three loop cards, what else could be the problem?
Any suggestions?
A lot of explanations might depend on the type of control panel and system protocol.
If the fault reporting is really as weird as you are suggesting, then I would look out for earth faults. Earth faults have provided me with some really strange device fault reporting in the past.
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Could be! I will see tomorrow, it's an advanced system with Apollo devices, but the system has been recently replaced, the old one I am not sure what it was, the only thing I am sure about it's the old existing Pyro cabling... etc
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Benz
im with wiz as usual and could possible be an earth fault but i would recommend however that you check that you have not muted the fault over 5 times as this locks the fault and even though you have cleared it,it will still show fault until you do a warm start with the reset button to the left of the loop cards on 4200 44400 and 4800 or behind the lcd display on a 4100.
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Is it the panel shutting the loop down on one side or an isolator , I would have out the loop isolators in the field and then start checking the loop out.
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Benz
im with wiz as usual and could possible be an earth fault but i would recommend however that you check that you have not muted the fault over 5 times as this locks the fault and even though you have cleared it,it will still show fault until you do a warm start with the reset button to the left of the loop cards on 4200 44400 and 4800 or behind the lcd display on a 4100.
Muting the fault 5 times will lock the fault...? This is new to me, I will try proving it next time..., but resetting Advanced panel from the internal reset button, this will wipe out all the info though?
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Is it the panel shutting the loop down on one side or an isolator , I would have out the loop isolators in the field and then start checking the loop out.
Indeed the short circuit is in one end of the loop by the panel..., the weird things is that the cabling are hidden, there is no way to chasse them, also addresses are not in order, say you have add: 27 in room 301 but add: 28 may be in the other side of the corridor in a different floor... etc
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Benz
im with wiz as usual and could possible be an earth fault but i would recommend however that you check that you have not muted the fault over 5 times as this locks the fault and even though you have cleared it,it will still show fault until you do a warm start with the reset button to the left of the loop cards on 4200 44400 and 4800 or behind the lcd display on a 4100.
Muting the fault 5 times will lock the fault...? This is new to me, I will try proving it next time..., but resetting Advanced panel from the internal reset button, this will wipe out all the info though?
no
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Could be! I will see tomorrow, it's an advanced system with Apollo devices, but the system has been recently replaced, the old one I am not sure what it was, the only thing I am sure about it's the old existing Pyro cabling... etc
Thats good news Benz. Its time you had a real problem to keep that over active mind of yours busy.
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have you checked the panels status in the view option. I would think the panel would show up earth fault but look at the earth monitor and it should sit at about 1.5v. 3.5v and above is a pos to earth fault and -0.4 is a neg to earth fault.
I would also note that if you are working in commission mode then the panel will only drive one way so if you have an o/c-all devices after this o/c will be missing.
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Benz
im with wiz as usual and could possible be an earth fault but i would recommend however that you check that you have not muted the fault over 5 times as this locks the fault and even though you have cleared it,it will still show fault until you do a warm start with the reset button to the left of the loop cards on 4200 44400 and 4800 or behind the lcd display on a 4100.
Muting the fault 5 times will lock the fault...? This is new to me, I will try proving it next time..., but resetting Advanced panel from the internal reset button, this will wipe out all the info though?
no
Sorry but you are wrong mate
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Could be! I will see tomorrow, it's an advanced system with Apollo devices, but the system has been recently replaced, the old one I am not sure what it was, the only thing I am sure about it's the old existing Pyro cabling... etc
Thats good news Benz. Its time you had a real problem to keep that over active mind of yours busy.
Indeed I spent 2 days now, trying to find out the short circuit, after opening so many devices to investigate..., and connect them back, the short circuit just disappeared on its own, and now it's rather an open circuit... etc, but all devices came back to normal now ..., good progress though
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Benz
im with wiz as usual and could possible be an earth fault but i would recommend however that you check that you have not muted the fault over 5 times as this locks the fault and even though you have cleared it,it will still show fault until you do a warm start with the reset button to the left of the loop cards on 4200 44400 and 4800 or behind the lcd display on a 4100.
Muting the fault 5 times will lock the fault...? This is new to me, I will try proving it next time..., but resetting Advanced panel from the internal reset button, this will wipe out all the info though?
no
Sorry but you are wrong mate
Sorry but YOU are WRONG mate..... give Advanced a call and ask them
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Benz any beam detectors on that loop?
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Benz any beam detectors on that loop?
Yes about 3 or 4
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Benz any beam detectors on that loop?
Good call GregC!
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Benz any beam detectors on that loop?
So what's the relationship between beam detectors and this issue?
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We had a problem a few years ago with beam detectors on a loop.
If I remember correctly, there were random activations of isolators that caused open circuit faults at the panel but were never seen on the circuit when we went ot test.
It turned out that in the small print of the installation data you have to fit isolators either side of the beam betectors, when the panel was refreshing its checksum, the initial start up current draw of the beam ddetectors was enough to activate an isolator, by having an isolator either side it cured the problems.
Might not be what you are experiencing but given you have 30 devices missing I would suspect you have a beam detector or similar device thats causing the loop to overload and bring in the isolators.
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Indeed, it might be worth finding out exactly what is on the loop and doing a loop calculation to see if the loop is overloaded, as this will cause spurious faults, and is quite often a common problem.
Or try breaking the loop half way roughly, and running both legs on two separate loops cards, thus halving the current requirement per loop.
What type of beam detectors is it? manufacturer? reflective type or not?
Are they loop powered or conventional type via input modules?
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We had a problem a few years ago with beam detectors on a loop.
If I remember correctly, there were random activations of isolators that caused open circuit faults at the panel but were never seen on the circuit when we went ot test.
It turned out that in the small print of the installation data you have to fit isolators either side of the beam betectors, when the panel was refreshing its checksum, the initial start up current draw of the beam ddetectors was enough to activate an isolator, by having an isolator either side it cured the problems.
Might not be what you are experiencing but given you have 30 devices missing I would suspect you have a beam detector or similar device thats causing the loop to overload and bring in the isolators.
Possibly, but technically speaking, how a beam detector causes short circuit isolators to trigger in either ways?
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Indeed, it might be worth finding out exactly what is on the loop and doing a loop calculation to see if the loop is overloaded, as this will cause spurious faults, and is quite often a common problem.
Or try breaking the loop half way roughly, and running both legs on two separate loops cards, thus halving the current requirement per loop.
What type of beam detectors is it? manufacturer? reflective type or not?
Are they loop powered or conventional type via input modules?
The loop was sitting OK for 3 years or so with no problem, why it should be over loaded only now?
But for the type of the beam still need to find out!
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OK, thought there may have been some recent alterations or something which could shed some light on it. I know the loop card flashing LEDs have been mentioned, but have you tried swapping out the loop card for another?
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With the Apollo devices, are the isolators integral to the devices or standalone isolators? We've had problems with isolators in Apollo call points in the past causing rogue problems. Replacement of the faulty device (once traced) overcame the problem.
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The problem with beam detectors and isolators is that beam detectors take a higher start up current that they do in normal operation, when a panel carries out its checksum count it powers down the loop and re energises the devices this is what caused our problem, it wasnt every night but common enough for us to pinpoint the problem.
Our system was running for some time before these faults started to appear
In your situation I would be looking at the beam detectors to make sure isolators are fitted either side, maybe an isolator is your problem?
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OK, thought there may have been some recent alterations or something which could shed some light on it. I know the loop card flashing LEDs have been mentioned, but have you tried swapping out the loop card for another?
I didn't swap the loop cards over, since they were all flashing ok, and also the left legs of the loops had short circuit which confirms he problem relies within the cabling rather than the loops card...
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With the Apollo devices, are the isolators integral to the devices or standalone isolators? We've had problems with isolators in Apollo call points in the past causing rogue problems. Replacement of the faulty device (once traced) overcame the problem.
The short circuit isolators are above detectors, have found in the first visit only one triggered, which means the next one could be the that end of the loop, but the day after was OFF, up till now we don't know what caused it to trigger, it's now an open circuit...
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Water water everywhere and not a drop to drink.
Ask yourself this...what causes a loop fault ?
Faulty device
Faulty Loop Card ( sometimes faulty due to a field device or lightning strike )
When you have checked the probable..look at the impossible.