Tamper loop max resistance range

Irish Steve

Hi Folks,

Have an old Scopetronic Vista 5 panel that's been working fine, and still is working, but have been annoyed recently by an intermittent Tamper fault on one of the zones.

I know it's a zone as I have a spare zone on the panel, so I moved the suspect zone to the spare, and the fault moved with the change, so that clears the panel.

A good while back now, we had a problem with a vibration sensor in the bathroom that got damp, and started triggering faults, so that got replaced. Based on that previous experience, I've swapped out the sensor and the mag reed, even though the reed is only a return short on the tamper, but that didn't nail it.

There are 5 windows, each with a junction box, a vibration sensor and one or 2 reeds on the windows, and one door with a reed in the loop. Wire run is probably about 40 Metres total. At present, there are no EOL resistors being used, it's a closed line loop.

When it goes off, a user reset clears the fault, and it may well be 2 or 3 days before it goes again, and I've tried leaving it in tamper soak for a good while in the hope that it would go solid, but no luck. There's no specific time of day, and it goes if the alarm is set and when unset. There's not been multiple fails in a short period at any stage.

There one junction box in the roof void, a cable got damaged during some repairs a while back, so that meant dropping a new wire into the room from above, so 2 were replaced with one, and a JB put in above the ceiling to link the 3 again, as channeling the wall wasn't an option at the time, so a thin drill was used to run up behind the plaster, and then the small holes at the edge of the lintel filled after the wire had been pulled in. As this JB is in a colder area, and possibly subject to moisture, I'm wondering if it would be better to use crimp connectors in a JB instead.

All the screws have been checked for being tight, and all the JB's and Vib sensors have been tamper walk tested with no apparent fails.

Starting to run out of ideas, so suggestions appreciated, and also an idea of what the max resistance of a closed loop can go to before the panel throws a hissy fit. If need be, I can change to EOL resistor fitted, I have panel access and the manuals to allow the changes to the settings.

Thanks

Steve

altor

It is very hard to find an intermittent problem, especially with all the sensors and junction boxes you have on the loop. At lease you know it is to do with the tamper. More than likely one of the tampers is faulty on anyone of the devices and the device needs to be replaced.

What I would suggest you do is disconnect the tamper in one device half way through the loop and close this off from the other devices, so only half the devices will be tampered. If the tamper pops up again then you know it is more than likely on the devices tampered that you have connected to the control panel. If it does not show then work towards the end of the loop closing off the loop in the same way. If it does, do the same back towards the control panel till you do find the faulty tamper on devices you have installed. Gel crimps are a better solution as the provide a gel seal to the cable ends making them water tight.

Irish Steve

altor wrote: »

It is very hard to find an intermittent problem, especially with all the sensors and junction boxes you have on the loop. At lease you know it is to do with the tamper. More than likely one of the tampers is faulty on anyone of the devices and the device needs to be replaced.

That was my first suspect, and the bathroom was the top of the list, based on previous experience, and the screw in the vib sensor being a bit loose. It's not as bad as it seems, as there's no tamper contact on the reeds as such, so that's just a straight loop back. The main suspect now is that roof JB, as all the others are easy access and have already been walk tested, the roof one wasn't so easy, but I've managed to get to it this afternoon, and I suspect a loose tamper connect there at the moment.

What I would suggest you do is disconnect the tamper in one device half way through the loop and close this off from the other devices, so only half the devices will be tampered. If the tamper pops up again then you know it is more than likely on the devices tampered that you have connected to the control panel. If it does not show then work towards the end of the loop closing off the loop in the same way. If it does, do the same back towards the control panel till you do find the faulty tamper on devices you have installed. Gel crimps are a better solution as the provide a gel seal to the cable ends making them water tight.

That was the sort of idea I was working with, I was going to go slightly further than that, and drop a temporary cable from the panel to the mid point, and put the rest of the zone on to the spare zone on the panel, so that I can see if it's the first section or the second section, and then if it's still being a pain, I can move the zone split one way or the other, and hopefully nail it that way.

Been at the zone earlier with the multi meter, and that's why the suspicion of the JB in the roof, as it seemed to be high impedance in that direction, so I've had a go at that JB, and have 10 Ohms on the zone right now, hence the Q about the total for a zone, and if it's worth going EOL with it, as that will put 1K at the end of the zone. !0 Ohms seemed OK, but I don't have a figure for what the top limit of a zone could be without the panel getting upset.

A bit more testing to do, and I have some gel crimps, so that's the next move.

Cheers

Steve

altor

You would be well under the limit on 40 meters. Is there no tamper on the devices?

Irish Steve

There are tampers on all the junction boxes and the vibration sensors, all of which have been checked, using walk test, and the lids have been removed and all the screws checked for tight and any corrosion or similar.

There's only a loopback on the reed switches, which is normal.

There was one JB that I couldn't check the first time round because I couldn't get to it easily, but that one has now also been checked, and while I'm not certain, I think there may have been a loose connection in that JB, I'll only know if it stops alarming over the next while.

It's been in soak test of the tamper zone for the last 4 hours, with no chirps, and it's gone colder tonight, so I'm hoping that maybe that's got it. If worst comes to worst, the zone gets split to isolate if it's the front of the house or the back that's the issue.

Thanks

Steve

altor

Irish Steve wrote: »

There are tampers on all the junction boxes and the vibration sensors, all of which have been checked, using walk test, and the lids have been removed and all the screws checked for tight and any corrosion or similar.

There's only a loopback on the reed switches, which is normal.

There was one JB that I couldn't check the first time round because I couldn't get to it easily, but that one has now also been checked, and while I'm not certain, I think there may have been a loose connection in that JB, I'll only know if it stops alarming over the next while.

It's been in soak test of the tamper zone for the last 4 hours, with no chirps, and it's gone colder tonight, so I'm hoping that maybe that's got it. If worst comes to worst, the zone gets split to isolate if it's the front of the house or the back that's the issue.

Thanks

Steve

Hopefully that was the issue Steve, any other problems let us know.