Door Entry Hikvision Intercom and gate controls worked fine suddenly stopped working?

[HNS]

Hi,

I wonder if anyone can help. Probably more of a gate question but using the Hikvision intercom.

Yesterday I replace a analogue GSM gate intercom system with a Hikvision IP intercom. In addition to the intercom there are safety sensor on the post and an approach pressure plate of some sort to allow it to open for vehicles.

I got it all in and had the connectors on comm and NC. With this the intercom and gates control via the intercom functioned fine but I realised the safety sensor and pressure sensors were not longer working. I tried switching the NC to NO and everything worked fine, gates, all sensors and intercom worked exactly as expected. I tested everything multiple times to ensure it was all fine. The customer also had a fob which still functioned as expected.

Today the customer told me the gate is stuck open. I have just spent a couple of hours there and I can't understand why it is not working anymore. Nothing has changed but the gates refuse to shut. If I switch back to NC the gate work but the sensors don't.

The only thing I can think might have happened is the approach pressure sensor is stuck, maybe from where my van was parked on it yesterday. Although it was still working for a least 3-4 hours after that.

Any ideas on what the issue might be would be greatly appreciated!

 

[JB1970]

Hi,

I wonder if anyone can help. Probably more of a gate question but using the Hikvision intercom.

Yesterday I replace a analogue GSM gate intercom system with a Hikvision IP intercom. In addition to the intercom there are safety sensor on the post and an approach pressure plate of some sort to allow it to open for vehicles.

I got it all in and had the connectors on comm and NC. With this the intercom and gates control via the intercom functioned fine but I realised the safety sensor and pressure sensors were not longer working. I tried switching the NC to NO and everything worked fine, gates, all sensors and intercom worked exactly as expected. I tested everything multiple times to ensure it was all fine. The customer also had a fob which still functioned as expected.

Today the customer told me the gate is stuck open. I have just spent a couple of hours there and I can't understand why it is not working anymore. Nothing has changed but the gates refuse to shut. If I switch back to NC the gate work but the sensors don't.

The only thing I can think might have happened is the approach pressure sensor is stuck, maybe from where my van was parked on it yesterday. Although it was still working for a least 3-4 hours after that.

Any ideas on what the issue might be would be greatly appreciated!

It could be a number of things. The 'pressure plate' that opens the gate automatically is likely just an induction loop or sensor in the surface of the road. When a vehicle moves onto it, the analyser board to which it's connected changes the state of a relay which is set to pulse or presence (pulse will do just that, presence will keep the relay in its changed state until the vehicle clears the loop). It wouldn't 'stick'. Safety circuits whether active infra red beams, pressure strips or induction loops are always closed circuit going open when activated ( as they must be fail safe)

I'd look at the programming of your intercom first. The gate controller will likely be expecting a common/normally open pair going closed to command an open signal (so you wire to com/no of the intercom relay). The relay output of the intercom should be set to 1 second as a brief pulse will trigger the gate controller.

As it was working when you left, something must have changed as it sounds from your description that the wiring is correct. Either (as you mentioned) the sensor that triggers the get is stuck closed circuit (it's normally open going closed) or the common/normally open of the intercom output has stayed closed (faulty, time schedule set?). Both of those can be checked in moments with a multimeter.

 

[HNS]

Thank you for replying and for the info on the pressure plates and sensors.

The intercom is wired and does exactly as you describe.

What it doesn’t explain is why it worked fine yesterday and then stopped working the next day.

 

[JB1970]

Thank you for replying and for the info on the pressure plates and sensors.

The intercom is wired and does exactly as you describe.

What it doesn’t explain is why it worked fine yesterday and then stopped working the next day.

The customer said the gate is stuck open. The safety being activated (open circuit) would cause that, but if it were the safety circuit at fault it would stay open regardless of how you had the open signal connected. You've said that when you inverted the intercom from com/no to com/nc the gate closed. That (to me) would indicate that the com/no of the intercom output is in a permanently closed state; you'd probably find that with the gate stuck open, removing either of the pair at the intercom (opening the circuit) would cause the gate to drop closed after its programmed auto close time. You've correctly got the gate controller connected to com/no of the intercom. Just disconnect that pair and check the resistance across them to prove that they are open circuit as they should be. The com/no open of the intercom will be in parallel with the com/no of the sensor/loop that opens the gate automatically. It's possible that the intercom output is not a truly volt free contact. You could try simply reversing the pair (no to com, com to no). I had an issue with connecting a Hik intercom to a wireless bell push where it would only work one way around.

The easiest thing to do though is get a manual for the specific gate controller. There will usually be LEDs showing the status of the open, close, stop and safety so you would know at a glance what's going on.