Contact Sensor *Faults* ?

[brucecampbell]

I have a beam sensor at the entrance to my driveway.
One of these cheapies to be precise: 
https://www.ebay.com/itm/100M-Dual-Beam-Photoelectric-Infrared-Detector-Sensor-Alarm-Home-Garden-Security/352735894912?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160908105057%26meid%3Dc3dfb5eaa12a481ab904fe4a7caf2cd1%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D352735894912%26itm%3D352735894912%26pmt%3D1%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100675.m4236&_trkparms=pageci%3Ad5131dbe-121e-11ea-be73-74dbd180a978|parentrq%3Ab3bb39eb16e0ac3c5e06ade6ffdb887e|iid%3A1

 

It is plugged into an HC300 via 12V and SIG
I have recently started to get false triggers through out the day and night - which is annoying as it turns on lights.
At first I thought it could be my HC300 starting to pack it in - as I have already replaced the power supply - so maybe other parts are coming to an end.
So I plug it into my HC800 to test - however it does not even work on the HC800 - so I'm thinking perhaps the cable is too long (~80 mtrs each way) and the problem is voltage loss.

Is there an easy way to add external power supply to the 12V - SIG loop for contacts? (assuming voltage loss is to blame here)

Thanks.

 

[Cyknight]

Depends on wiring on and to the sensor.

*Assuming you only have 3 wires:

12v DC power supply, neg to ground on controller and to neg on sensor, pos to sensor

sensor back out to sig on controller.

This bypasses using the controller for power output completely

 

*Could also be that the draw to power the device is too much. If it's a 4 conductor wire and the beam has 4 terminals, you could leave 12 and sig connected to the appropriate connections on the sensor, and use the other conductors to power the device itself.

 

*Push comes to shove you could rewire the whole thing to have it's own power supply and the signal from it to directly close a small 12v DC relay, and wire the relay connection back to the controller

[brucecampbell]

6 minutes ago, Cyknight said:

Depends on wiring on and to the sensor.

*Assuming you only have 3 wires:

12v DC power supply, neg to ground on controller and to neg on sensor, pos to sensor

sensor back out to sig on controller.

This bypasses using the controller for power output completely

 

*Could also be that the draw to power the device is too much. If it's a 4 conductor wire and the beam has 4 terminals, you could leave 12 and sig connected to the appropriate connections on the sensor, and use the other conductors to power the device itself.

 

*Push comes to shove you could rewire the whole thing to have it's own power supply and the signal from it to directly close a small 12v DC relay, and wire the relay connection back to the controller

Thanks for the input.

The sensor is powered by an independent power supply, it is solely the contact I am having trouble with.
excluding the power supply, I have two wires.
Wire 1 from HC300 12V to Sensor COM
Wire 2 from HC300 SIG to Sensor NO
This set up works - when the sensor beam is broken, the sensor alarm light glows and the HC300 registers the contact and my programming is run (lights go on).

The reason I am debugging is I am getting loads of false triggers.

So I tried moving the contact to my HC800 - but this did not work at all - so I figured maybe my HC800 is already using too much amps for the other relays and contacts - which got me thinking maybe the HC300 can't handle sending 12V along a 160+ mtr loop of thin alarm wiring - so wondering if a boost would help - (if possible)

It could simply be a fault in the sensor - but I am not sure why the HC800 would not work for this set up when I have 3 others working fine.

 

[Cyknight]

11 minutes ago, brucecampbell said:

Wire 1 from HC300 12V to Sensor COM
Wire 2 from HC300 SIG to Sensor NO

So you'd go:

controller GRD to power supply negative

powersupply positive to sensor COM

sensor NO to controller SIG

But if voltage drop is the issue, a simple power supply may not work, you'd have to get a power supply with a voltage regulator (manual or automatic) to feed a higher voltage output to compensate for the drop on the other end.

[brucecampbell]

 

13 minutes ago, Cyknight said:

So you'd go:

controller GRD to power supply negative

powersupply positive to sensor COM

sensor NO to controller SIG

But if voltage drop is the issue, a simple power supply may not work, you'd have to get a power supply with a voltage regulator (manual or automatic) to feed a higher voltage output to compensate for the drop on the other end.

Thanks, I'll run some tests on the wires over the weekend. still pretty confused as to why it does not work with the HC800. - my garage door sensor is working fine in SIG 4 but changing to the driveway sensor got no response at all...

I do have some other sensors I could wire up temporarily to see if that eliminates the problem.
 

[brucecampbell]

Turns out the problem was a broken wire.

luckily I had run 6 core alarm cable and had two spare, so I could just change the wire.

The broken wire was still allowing about 2-4 volts, slight fluctuations must have been triggering the contact.