Alarm System?

Why did you not "have" it installed and started by professionals?

There's no diagnostics program?

Operator's manual?

No troubleshooting guide?

No qualified on-staff personnell?

No vendor support indicates a cut-rate supplier that does not care about customer service.

Remember, you get only what you pay for.

Can you give some indication that you may have tried some remedies yourselves.

PC1616/PC1832/PC1864 User Manual - DSC

Security System Control Panel - PC1832 | DSC ...

How to use your DSC Security System - Full Video - YouTube

Thanks for the comments.

This site is in a remote section of Africa. The cost to get a "professional" installer to site was cost prohibitive.

We had installed a similar system earlier and it has been working fine.

Diagnostics on the system show all zones are good.

We are qualified but evidently this is a bit above our pay grade.

The vendor is happy to send a tech to site but that brings us back to the first point mentioned.

Lyn, thank you. but I have and have seen all the links you mentioned.

The 2 offices we have secured have windows and those zones do not have any issues. The diagnostics show the "fault" actually, alarm; comes from the latest Zone that was added which consists of the PIR sensors installed in steel (overseas type) shipping containers. One of the previously installed Zones has 6 PIR in series. This zone has been working fine. When adding the additional Zone with 10 we started having problems. This new Zone we can keep it working but with only 5 PIR sensors.

Other than a yard security light there is no electrical interference. No radios, no cars, no lights, not a single luxury.

We have monitored the power supply , measured the resistances on the cables to the different zones.

In the evening when the system is activated the sun is on the back side of all the containers. The sensors are all mounted at the front (door end) facing East. Containers are all empty so no mice or rats. Maybe some spiders but they can't be that good that they know when we activate the alarm and set it off 5 minutes later.

I was disappointed that I was not able to get any support from the parent company. All I was looking for was some data on how many PIRs and what the maximum distance would be for a Zone installation, as that is my hunch of what is causing the issue.

I think connecting PIR sensors in series brings down accuracy. Can't you get more separate inputs? Or an alarm system with digital addresses?

Your Pir sensors point to a steel wall where the sun is at? How is the temperature of the wall inside changing? What color is the wall inside and outside?

Have you been inside when locked?

No light beams or straw lights?

That was what i was trying to determine was the operational effects of running that many in series.

We ran out of cabling to make anymore individual zones.

There are no light beams or straws.

the inside walls are flat red oxide (looks like red primer coat) or flat grey. Outside is flat red or ivory (cream . Morning sun gets hot but also on the containers that are working. I haven't gotten any actual temps.

I'm heading out to the site tomorrow to look it over again to see what we can do as they want to use the remaining containers now

Are there windows involved? Sun, steel container bodies?

Pir sensors also could signal variations in temperature (steel surfaces) or light variations (windows)

A little troubleshooting is called for...

http://www.zen22142.zen.co.uk/ronj/fls.html

Who manufactures the SENS-1200 units (or, better, can you supply a link to a datasheet)? A Google search was unproductive. What is the resistance of the loop of 10 PIRs in series?

Alarm sensors frequently have a resistor in series with the alarm contacts, and sometimes another in parallel, so that tampering (short circuiting, or cutting the cable) can be detected. It's possible that this PIR has such resistors, and that the total resistance of several in series is too close to the tamper detection limit of the control unit (which is kinda what SHOCKHISCAN was saying in #11, and what I was trying to establish above).

Hasn't been mentioned yet, but another thing to check might be the end-of-line resistor to make sure it is of the right resistance. Since you installed the other zones with no problem I'm sure you have checked that when you added this zone.

Check that no building and no container contains unwanted higher biological entities:

• Mice
• Rats
• Dogs
• Feral cats
• Birds
• Illegal immigrants
• Etc., etc.

Your zones respond to current draw, not a closed contact (although that is the ultimate current draw).

Check your current draw on this zone.

Another couple of possibilities:

1. One of your sensors is bad

2. You have something in the area of this fourth zone which emits some type of RF radiation.

3. You have a wiring issue.

The End-Of-Line resistance/impedance device is most likely not correct.

It is imperative that you install the correct size resistor and/or other device at the end of the sensor circuit.

The needed information for sizing the EOL should be available in the OEM installation manual.

If not, then measure each circuit current flow in the circuits that are operating correctly then calculate the size of resistor needed in the problem circuit that will raise or lower the current flow to match the operating trouble-free circuits.

THere is no EOL resistor in these circuits. A tamper switch and the output switch are all in series with all the PIR sensors.

WE placed the last 10 sensors on 2 zones with 5 sensors each. So there are now 5 separate zones. Zone 5 is still having problems as it alarms after about 40 minutes with nothing apparent in the zone.

The resistance on each circuit (zone) varies. Zone 3 is close to the panel with only 2 sensors with a resistance of 53 ohms. Zones 4 and 5 each have 5 sensors and farther away, measure 210 and 235 ohms.

Each of the 5 zones are drawing 0.7mA on the switching circuit. We are using 22 AWG and the OEM manual says that is good for 3000 ft. Our longest run is about 1400ft.

THe power supply for the panel is rated 12VDC at 500mA. Total load with all zones was 180mA. and 13.6 VDC at the panel.

We noticed that the power voltage at the last sensor on zone 4 (which is working correctly) was 9V. The voltage on the last sensor on zone 5 was 8.7. The voltage on the first sensor on zone 5 was 9.5V. When the other 4 sensors were removed from the circuit the voltage went to 12V. The single sensor was drawing 13mA but when the other sensors were added back in the current stayed the same but the voltage dropped.

Not sure what gives there.

The silk screen on the circuit card of the sensors showed the name SensorPro SENS1200-Q. Not been able to find anything on this critter.

Going to look at this again tomorrow to see if there is a bad sensor we can isolate.

any other ideas?

You likely have a bad sensor on (now) Zone 5.

Also, if your readings tell you that 5 sensors are drawing the same current as 1 sensor, your meter is bad as well.

I would wirenut the "in" and "out" wires at each sensor together, one at a time to determine if you have a bad apple.