Alarm input for missing power?

[DarkGlobe]

Hello, i've powered my nvr and my cams with an UPS, so they can still working while missing electrical power.

I would like to be notified when power is missing. On the back of my nvr there are 4 input "ports" and I've thinked to connect the output of a simple power adapter (maybe 5 or 12v), of course the power adapter will not been connected under the ups.
Then configure a NC input alarm in the nvr settings and it should notify me when there is no power.

Is my thinking correct? Should it work?

 

[eggsan]

If you plug a 120Vac relay directly to “surge only” output of the UPS, the relay will change state during power failure. Likewise, use the relay contacts to interface your NVR

Edit: understand your approach to use the power adapter will work as well, probably no need for a separate relay. Check the NVR spec’s. You may try it by yourself, by connecting a short cable (momentary) between COM and INPUT. I prefer a passive connection, instead of voltage (5/12Vdc)

 

[eggsan]

Not sure about your particular model, but should apply as well. There is an “alarm input”, able to handle your “power pack” voltage. Connect the power pack to your “surge” UPS outlet. Just connect the + terminal to selected input (remember to include in your settings), while the - terminal to GND (up to 2A dc). But remember, check yiur specific model first.

 

[DarkGlobe]

If you plug a 120Vac relay directly to “surge only” output of the UPS, the relay will change state during power failure. Likewise, use the relay contacts to interface your NVR

Edit: understand your approach to use the power adapter will work as well, probably no need for a separate relay. Check the NVR spec’s. You may try it by yourself, by connecting a short cable (momentary) between COM and INPUT. I prefer a passive connection, instead of voltage (5/12Vdc)

Not sure about your particular model, but should apply as well. There is an “alarm input”, able to handle your “power pack” voltage. Connect the power pack to your “surge” UPS outlet. Just connect the + terminal to selected input (remember to include in your settings), while the - terminal to GND (up to 2A dc). But remember, check yiur specific model first.

Thanks for the replies.

The NVR is the HikVision DS-7608NXI-K2 (DS-7608NXI-K2).

I've thinked to use a relay, but probably the relay coil will blow up after few months because is always under tension.

I've found this pdf, but i'm not sure if is valid also for my nvr, where is indicated a voltage of a maximum 12v for alarm inputs:

https://www.hikvisioneurope.com/eu/portal/portal/Technical Materials/24 How To/CCTV/How to use NVR Alarm Input Output Function.pdf

 

[tigerwillow1]

You really need to find the specs for your specific NVR or somebody who knows how it works. Using my Dahua NVR as a random example, for starters, the manual is about as close to useless as it could be. The NVR data sheet is much more helpful, saying "Low Level Effective, Green Terminal Interface", which tells me the way to trigger is to connect the alarm input to NVR ground. Your NVR could be totally different from this. Would connecting an external power source to that harm anything? I don't know. Out of paranoia of burning something up, I use an optocoupler to trigger the alarm input. The PDF you found appears to agree exactly with how my Dahua NVR works, but does it apply to your model? If your alarm inputs do in fact float at some positive voltage, you could try grounding them through a resistor to limit the current. As an example, my Dahua NVR inputs trigger when grounded through a 3.3k ohm resistor. They do not trigger with 4.7k ohms. A continuous duty relay should operate for many years 24x7, or you could go the route I did with a PC817 optocoupler. They cost less than a dollar.

 

[eggsan]

As long as not exceeding the coil current, should be no problem. It also applies to keeping the power pack connected at all times. It is a matter of connecting the N.C. Relay output (is open while energized) while connecting directly to the N.O. Input (NVR default). To confirm the operation, just short both Input-x to ground (after programming for Input-x). It wont hurt anything.

 

[DarkGlobe]

You really need to find the specs for your specific NVR or somebody who knows how it works. Using my Dahua NVR as a random example, for starters, the manual is about as close to useless as it could be. The NVR data sheet is much more helpful, saying "Low Level Effective, Green Terminal Interface", which tells me the way to trigger is to connect the alarm input to NVR ground. Your NVR could be totally different from this. Would connecting an external power source to that harm anything? I don't know. Out of paranoia of burning something up, I use an optocoupler to trigger the alarm input. The PDF you found appears to agree exactly with how my Dahua NVR works, but does it apply to your model? If your alarm inputs do in fact float at some positive voltage, you could try grounding them through a resistor to limit the current. As an example, my Dahua NVR inputs trigger when grounded through a 3.3k ohm resistor. They do not trigger with 4.7k ohms. A continuous duty relay should operate for many years 24x7, or you could go the route I did with a PC817 optocoupler. They cost less than a dollar.

As long as not exceeding the coil current, should be no problem. It also applies to keeping the power pack connected at all times. It is a matter of connecting the N.C. Relay output (is open while energized) while connecting directly to the N.O. Input (NVR default). To confirm the operation, just short both Input-x to ground (after programming for Input-x). It wont hurt anything.

Unfortunately there are to many doubts about working specs of these input pins. Where can i found something more detailed about my nvr model? Should i contact directly HikVision via email?
Anyway using a relay or a dc power adapter, i always don't know if can i apply a tension in input or just short the GND and an input pin with a relay.

What would you do?

 

[spuls]

We use a simple battery powerd GSM Modul like the GA01P GSM what is powerd by the same source as our servers/network. In case of an power outage or ups failure, it is able to call you or send an message via sms.

Robot or human?

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it also is able to react on an external input contact our could be used as "output" to an external device.

 

[eggsan]

Is basically contact closures interfaces (NO/NC) for both Input/Output connectors. Just do not exceed the amps rating, specially while using the Output pin (controlling a siren, strobe, light). It is normally about 1 amp DC, but you may add an external relay for higher currents. But using the Inputs, is just shorting (no voltage) the input to ground.