Scantronic 9751 OP3

[Fletch83]

I am wanting to connect a volt free contact to my Hikvision NVR so that when the alarm is set I can trigger the input on the NVR to start alerts etc. 

 

I just cannot workout what OP3 is, if volt free I would have expected to see a ground terminal so I can connect to OP3 and ground and then this would act as a switch for the NVR. 

[sixwheeledbeast]

Volt free would be a relay so would be marked COM/NC/NO, if it's a single terminal it will be switched output so you will need a relay.

Manual will say if it's +ve/-ve applied or removed then you need to use an auxiliary voltage for the other coil side of the relay.

 

Should be transistorised relay too due to possible back EMF.

[PeterJames]

or just connect a relay to the output and voila! 

[aissecur]

As above, I would use a 12v dc relay personally and power it from a little 12v independent psu (as it’s an NVR you probably won’t have a 12vdc PSU powering any cameras as everything will likely be Poe) 

[sixwheeledbeast]

Wouldn't expect the NVR needs 12V just a closed loop on it's own input/output, hence needing a relay.

Voltages shouldn't be shared between them

[james.wilson]

Agreed

[PeterJames]

12 hours ago, aissecur said:

As above, I would use a 12v dc relay personally and power it from a little 12v independent psu (as it’s an NVR you probably won’t have a 12vdc PSU powering any cameras as everything will likely be Poe) 

He is after a voltage free output, and the panel will drive the relay, adding another PSU will only complicate things