[Right Control]

I've been asked by a large school district if I could incorporate the sunrise and sunset times into their lighting controls for on/off control of the lights. I was looking at the weather service in N4 and messing around with it today. Anybody used the sunrise and sunset times from this? I'm wondering about fail safe to a schedule for backup, and what the actually programming is? Just maybe comparing current time with the sunrise and sunset times? Never done it before, and any feedback would be appreciated.

 

[kontrolphreak]

So I did this with another system. Easiest fail safe would be a photocell as backup.

For my application I did the sunset/sunrise programming in the main supervisory/router and had all other controllers get the times from it, if the local controller lost communications to that controller depending on the month it used a local summer or winter schedule. Large casino with a lot of outdoor lighting on the system.

You could do the same with the photocell as secondary backup and if comms to that controller also went down then roll to the local schedules. Best to use a analog photocell so that you can monitor when the light begins to increase or decrease and not just a contact. Also install the device in a shaded location out of the direct sunlight.

kontrol out

 

[orion242]

Just use the sun position block in the weather service jar. That just uses lat/lon & station time to calc sunrise / sunset. Pretty solid and doesn't go down every other month like the weather service.

Analog light sensor is another solid backup.

 

[JSLLC4Life]

Just use the sun position block in the weather service jar. That just uses lat/lon & station time to calc sunrise / sunset. Pretty solid and doesn't go down every other month like the weather service.

Analog light sensor is another solid backup.

I agree with this. I set exterior lighting to usually come on once the sun is at 3 degrees or less of elevation. My experience is that this method is more reliable than even a photocell which can be covered with leaves and snow. I even inherited a project where the photocell picked up ambient light from the football stadium across the parking lot. For the love of all you hold dear in this world, do not use the weather service.

 

[orion242]

Light sensors need a good spot like OAT. If your doing sign lighting, almost need them as many want the signs on in bad weather etc.

That sun position block hasn't failed for me. Just work off the times and add an adjustable offset so they come on a bit before / after sunset & rise.

 

[jthompson]

That sun position block hasn't failed for me. Just work off the times and add an adjustable offset so they come on a bit before / after sunset & rise.

This exactly. I've had this sort of algorithm in place for years and never had the first complaint, in fact, it's been compliments because no one has to screw with a schedule or timeclock when daylight savings sweeps through. Photocells get leak, burn up, and otherwise fail. If the JACE has the correct date and time you're golden. Seriously though, listen to everyone else...DON'T get it from the weather service. Go to the weather module and use "SunPosition". Once you get started, read up on Unix time, it'll make your efforts a whole lot easier.

 

[Right Control]

Wanted to say thanks for all the input. The weather service was just a first thought. I've had many issues with it over they years like anyone doing tridium. So that's why I posted, and like usual got very good response ,and solutions. Thanks again