Parallel wiring

[nisafourar]

Hello, i want to connect two N.C magnetic contacts using parallel wiring in the auxilliary input of the Visonic MC-302E PG2?.

From the manual of the MC-302E PG2:
a.If the auxiliary input of the MCT-302E PG2 is defined as a Normally Closed (N.C.) type, series connected N.C. sensor contacts must be used exclusively. An E.O.L. resistor will not be required.

b.If the auxiliary input of the MCT-302E PG2 is defined as a Normally Open (N.O.) type, parallel connected N.O. sensor contacts must be used exclusively. An E.O.L. resistor will not be required.

c.For E.O.L. supervision:
Normally Closed (N.C.) sensor contacts can be used. A 47kΩ E.O.L. resistor must be wired at the far end of the zone loop.

Can i use a different resistor in the first magnetic contact using this parallel wiring?
Let's say a 2.2k in the first and 4.7 k in the second ? Would this cause a problem?
In that case i'll have two zones ?
Thank you very much.

 

[Europlex]

Before going into how, a question, WHY on earth would you want to do that?

 

[nisafourar]

Hello, i would like to use two magnetic contacts connected to the auxilliary input and i want to operate them seperataly.I don't know if this is possible.
Thank you for your interest.

 

[SimonH2]

As in "if either operates (opens) then <something> happens" ?

If so then you wire then in series as described - ie without a resistor.

If you wire them in parallel then nothing will happen unless both switches are operated (opened).

 

[nisafourar]

Thank you very much SimonH2.
So if i undesrtand correctly the following will happen.
Operation of two doors

In series wiring
1st Door Closed - Magnetic contact CLOSED - NO ALARM
2st Door Closed - Magnetic contact CLOSED - NO ALARM
No need for resistor

In series wiring
1st/2nd Door Open - 1st/2nd Magnetic contact OPEN - ALARM
No need for resistor

Parallel wiring
1st Door Closed - Magnetic contact CLOSED - NO ALARM
2st Door Closed - Magnetic contact CLOSED - NO ALARM

Parallel wiring
1st Door OPEN - Magnetic contact OPEN - NO ALARM
2st Door Closed - Magnetic contact CLOSED - NO ALARM

Parallel wiring
1st Door OPEN - Magnetic contact OPEN - ALARM
2st Door OPEN - Magnetic contact OPEN - ALARM

Can i use N.C contacts when i use this parallel wiring or i need N.O.Should i use in this case resistor?

What will happen if i use one N.C and one N.O ? And what if i want to use E.O.L wiring? What is the difference in the result of a magnetic contact having Tamper or E.O.L wiring.Wouldn't this have the same result?

I am a bit confused. All i want to do (if it is possible) is that:
I have two sliding doors (external and internal in the same frame).
In the summer i would like to open the internal for ventilation but still have the external closed.
In the winter both closed.

Can this be done using a combination of MC-302E PG2 and N.C or N.O contacts ? or i have to buy another MC-302E PG2 to do that?

Thank you all for your interest and sorry for this confusing questions.

Regards

 

[SimonH2]

Yes, the list of "doors open" vs alarm status is correct.


Alarms are somewhat outside of my knowledge area, but I'd have thought the correct way to deal with this would be to use a zone/sensor omit function so your can set the alarm while omitting a single zone or sensor.
So the outside door and inside door would be separate, and you'd have the option of having the system ignore the 'alarm' status from the inside door when you want to leave it open.

I know that at work, there were a number of doors that had a key operated switch to allow them to be opened without setting off the alarm - but I wasn't involved and know no more than that. I "assume" that the key switch simply shunted the magnet switch.


Alternatively, do you need a contact on the inner door ?

 

[nisafourar]

I don't think that i really need a magnetic contact for the internal door but i want to know if something like this could be done.
Propably i'll install the MC-302E PG2 with one surface magnetic contact to the exterior door and if i can i'll put a 4.7k resistor (how many Watts shoud be ? ) for E.O.L supervision.
Then i think that i'll deactivate the magnetic contact of the MC-302E PG2 and use only the auxilliary.
In case i want to install two magnetic contacts i think the parallel wiring could be most appropriate for this job.Only if both doors open then the alarm will go on. But now i would like to know if i can connect N.C contacts in parallel.
Thank you.
Something else :
http://tennesseealarmstore.com/index.php?main_page=page&id=17
"The normal position of the switch is how it behaves without the magnet close to the switch. Imagine the switch setting on a shelf and the magnet held in your hand. This would be the contact position at rest. So, in a magnetic switch with N.O. contacts, when the magnet is brought in close proximity to the switch, approximately one half inch, the contacts close. This is by far the most widely used configuration in modern DIY alarm systems.The other choice is the N.C. configuration, which is when the contacts are closed at rest, laying up on the shelf. When the magnet is brought close to the switch, the contacts open, breaking the circuit. Don't get normally closed switches confused with normally closed circuits"

http://www.diy-alarms.co.uk/catalog/which_mag_contact.php
"They are supplied as a pair comprising the magnet and switch and are available in Normally Closed (NC) and Normally Open (NO) versions. NC contacts are closed circuit when the magnet is in close proximity to the switch. NO contacts are open circuit when the magnet is in close proximity to the switch. NC contacts are almost exclusively used in intruder alarm systems where opening the switch (magnet on door moving away from the switch). NO contacts are used in applications where there is a requirement for the system to go closed circuit when the magnet is moved away from the switch, e.g some CCTV applications."

Which is correct?

 

[bernardgreen]

i'll put a 4.7k resistor (how many Watts shoud be ? )

Normal operation voltage is 12 volt ? Might rise in fault condition to full chaging voltage say 15 volts.

Watts = Volts times Volts divide by Ohms

therefore resistor wattage required is 15 * 15 / 4700 = 0.048 watts

 

[nisafourar]

Thank you bernardgreen.
The 47k resistor will be used with a surface magnetic contact and all this will be connected to the aux input of a wirelless magnetic contact (MC-302E PG2). This MC-302E obtains power from an on-board 3 V Lithium battery (Low Battery Threshold 2.2 V).
I don't know if this helps , but for this one using the formula the watt should be almost 0,002 watt.So what should be the max watt rating for this resistor? 1/4watt should be ok ? and 47k&#937; =4700&#937; or 47000&#937; ?
As far as the panel :
External AC/AC adaptor :Europe: 230VAC 50Hz input, 9VAC 700mA output.

Internal AC/DC:Internal switching power supply:Input: 100-240VAC,
0.12 A Max.
Output: 7.5VDC, 1.2A Max.

Current Drain:Approx. 70 mA standby, 1200 mA peak at full
load.

Backup Battery Pack:4.8V 1300 mAh, rechargeable NiMH battery pack, p/n GP130AAM4YMX, manufactured by GP or equivalent.

Thank you very much.