I installed a Lutron OPS2H occupancy sensor that is wired to a 120ac/12vdc to a 12vdc siren in a small cabin. It is controlled by a remote from the porch. Turning it off before entering works well, but turning it on switches the sensor and the siren operates until the delayed time resets it. Is there a sensor that will not switch when power is off and on again?
Occupancy Sensor Question
- Thread starter Bob49
- Start date
qcroanoke
Sometimes I don't know if I'm the boxer or the bag
- Location
- Roanoke, VA.
- Occupation
- Sorta retired........
Google motion or occupancy sensors with no test period on power up.
Thank you for the reply.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
Or put a simple delay on make timer in series with the siren like the ones often used to delay HVAC compressors should they be short cycled, sounds like you only need a second or so for delay.
Thank you for that information. The delay time on the sensor is 2.5 minutes before it resets. I thought about a delay between the sensor and the 120/12vdc power supply. Wouldn't that delay have to match the sensor delay? So if someone tripped the sensor, it would be 2.5 minutes before the siren is powered? I have been looking for a sensor with no test period on power up as qcroanoke suggested but haven't found one yet.
Barbqranch
Senior Member
- Location
- Arcata, CA
- Occupation
- Plant maintenance electrician Semi-retired
You can wire it so the delay only happens on powering up the circuit, not when triggered by an intruder (unless the intruder comes in within 2.5 minutes of you turning on the switch.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
The on delay relay KWired mentioned is adjustable, they can be set for several minutes, but I don’t know if they will work on dc.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
The ones marketed for HVAC compressors are often lesser cost, but may have certain limitations. You can get similar types often at higher prices with more options including AC/DC, some only run on specific voltage, some work over wide range of voltage. HVAC marketed ones typically are 5 or 10 minute max and marked in 1 minute increments. I have purchased some from Grainger at higher price that can have smaller increment adjustments. I somewhat commonly have needed delays between 5 and 60 seconds and used these for that. They still less than the octal or plug in cube style timers if you only need simple on delay function.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
I may not understood what issue you are having and this may not work. Sounds like your occupancy sensor powers up with an on cycle.
I was initially thinking it has output for just a short time upon power up and was figuring if that was only a second or so you could put an on delay in series with the siren - would delay the siren for that second or two every time it is called to run but that might be ok.
You maybe could use a more complex timer and have it interrupt the line to the siren upon initial power up - assuming you can have it silenced for that first 2.5 minutes and then return to normal operation.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
A simple relay powered by the timer will work, just break the siren with the dry contact. Once powered up, the siren will be able to trigger as normal.
Barbqranch
Senior Member
- Location
- Arcata, CA
- Occupation
- Plant maintenance electrician Semi-retired
You can get an Omron H3CA-A on eBay for under $25. I have used more than a dozen of them, some for more than 20 years, without a failure. Time range is 0.1 second to 9990 hours. On delay, off delay, recycle, etc by flip of a switch.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
On delay with coil connected to non controlled supply conductors. Run the siren through delayed normally open contact. Stays closed until power is lost. Cycles again when power restored.
Thank you for the reply. Having the delay wired after the sensor and delayed for 2.5 minutes keeps power off the siren until the sensor resets after 2.5 minutes. How would this be wired to avoid the delay when the sensor is triggered?
Thank you for the information on this relay.
Thank you for the reply. I was trying to delay the siren on power up but not have the 2.5 min delay when sensor is tripped. A sensor with no test period as qcroanoke suggested would solve the problem but I haven't found one yet.
Thank you for the reply. That solves the power up problem but I was trying to avoid a delay if the sensor is triggered. Since I haven't found a sensor that doesn't go into test mode on power up this might be the best it gets.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
You will only have the delay on initial power up. (Arming) after it is armed, there will be no delay. That allows a person to exit without tripping the siren, just like a normal burglar alarm.
kwired
Electron manager
- Location
- NE Nebraska
- Occupation
- EC
the timer needs powered directly by the supply and not through the sensor. only the sensor output goes through the timer contacts. Which means you need something other than the previously mentioned two terminal timers.
hillbilly1
Senior Member
- Location
- North Georgia mountains
- Occupation
- Owner/electrical contractor
The two terminal will work fine, you just have to power a relay that has a dry contact, and put it in the right place of the circuit. Those that don’t understand controls though, will have a hard time figuring it out.