If I unplug the siren the keypads go into an alarm state. I assume there is a resistor in the actual siren since there isn't one on the panel itself. On all of the zones, they put the resistor at the panel. I haven't been able to find what the resistor is on the siren to bypass it when I want to do some changes and to test various things without the siren also going off. Any idea on what the resistor value is for the siren?
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Siren bypass in an NX-8E
- Thread starter lanbrown
- Start date
Do you have a speaker or a real siren connected?
As a first guess, I would try a 10 or 12 ohm, 20W (or greater) resistor. You don't really need the high wattage for supervision, but if the alarm triggers, it's going to pass some significant current through it, and then the high wattage is required.
As a first guess, I would try a 10 or 12 ohm, 20W (or greater) resistor. You don't really need the high wattage for supervision, but if the alarm triggers, it's going to pass some significant current through it, and then the high wattage is required.
It's often difficult to tell the difference between a siren and speaker. Many sirens are just a speaker with a built-in siren driver circuit board, so they look identical on the outside.lanbrown said:I'm going to say it is a speaker; it is small but loud. The dog doesn't like it and I don't blame her.
Either way, I think the 10-12 ohm resistor should work. You might be able to get by with a larger resistor and still trick the supervision circuit, but you'd have to experiment with different values to see what works.
I wouldn't use the 1 ohm resistor all by itself as it is too much load for the outputs of the panel. Putting it in series with the 10 ohm resistor would be ok.lanbrown said:Thanks. I bought a 10 and 1ohm resistors. One is 25 watts and the other is 50 watts, so that should be plenty to handle the load. I'll see if either of those is enough to trick the panel.
RAL said:I wouldn't use the 1 ohm resistor all by itself as it is too much load for the outputs of the panel. Putting it in series with the 10 ohm resistor would be ok.
Sorry, meant 10 and 12 ohm.
You don't need nearly that small of resistor. I just did this and used 3.3k ohm. Not exactly the same board but the NX320 remote power supply/expansion module manual shows a diode in series with the siren and a 3.3k resistor to tell the panel the circuit is complete. There is a note that the diode and resistor is not needed if the bell is a commercial fire bell. Must be some condition that reverses polarity for that board. The NX-8E manual has a note that with some sirens a 3.3k resistor may be needed to prevent leakage current through the siren and low level of noise when off.
