Hi,
I have a small problem that i'm sure can be solved easily with some advice off here. Explaining the problem may be the issue though. here goes.
I have a "normally open" gate contact on a business premises, I also have a "normally closed" set of beams that are situated a few metres past the gate. I have wired both of these in parallel to a cctv system on a "normally closed" circuit.
The out come works perfectly, if the gate is closed and the beam is broken, the circuit goes open and an alarm is raised (a cctv picture gets emailed). If the gate is open, then this disables the circuit as the circuit remains closed due to the contact. Therefore the business is assumed open and the owner doesn't want constant emails due to the beam being broken.
The problem I have is if the business is closed, and a potential thief spots the beam, he could jump over it and then break in through the gate. No email would be sent! So I thought I would wire another pair of wires onto the same contact and attach it to a different alarm input on the system (normally open circuit). So if the gate opens then the second circuit would go "closed" and an alarm activation would occur. However, as the second pair of wires is connected to the same contact as the above circuit, (in parallel with the beams), the beams cause the second circuit to stay closed, when the gate gets shut. Ie it never gets to its normally open status. So is there anything I can attach to the second circuit that will stop the beams interfering? would a diode work? The other solution would be to install another gate contact and keep both circuits separate but i'm sure there is an easier way.
Hope someone can understand this.....
Thanks in advance
Alan
I have a small problem that i'm sure can be solved easily with some advice off here. Explaining the problem may be the issue though. here goes.
I have a "normally open" gate contact on a business premises, I also have a "normally closed" set of beams that are situated a few metres past the gate. I have wired both of these in parallel to a cctv system on a "normally closed" circuit.
The out come works perfectly, if the gate is closed and the beam is broken, the circuit goes open and an alarm is raised (a cctv picture gets emailed). If the gate is open, then this disables the circuit as the circuit remains closed due to the contact. Therefore the business is assumed open and the owner doesn't want constant emails due to the beam being broken.
The problem I have is if the business is closed, and a potential thief spots the beam, he could jump over it and then break in through the gate. No email would be sent! So I thought I would wire another pair of wires onto the same contact and attach it to a different alarm input on the system (normally open circuit). So if the gate opens then the second circuit would go "closed" and an alarm activation would occur. However, as the second pair of wires is connected to the same contact as the above circuit, (in parallel with the beams), the beams cause the second circuit to stay closed, when the gate gets shut. Ie it never gets to its normally open status. So is there anything I can attach to the second circuit that will stop the beams interfering? would a diode work? The other solution would be to install another gate contact and keep both circuits separate but i'm sure there is an easier way.
Hope someone can understand this.....
Thanks in advance
Alan