Gotcha. I've done a lot of work for Orthodox families over the years. Unfortunately, none of the systems currently on the market can directly support a Hebrew calendar. The way I got around that was to write a set of rules for Shabbat and Yom Tov, assign them names and then adjust the dates once a year. Sunset is easy with ELK. Using panels like the Napco P9600 I simply changed the sunset times four times a year.
I got involved in that a few decades ago when some dummy started burning synagogues and rabbis' homes in my town (West Hartford, CT). We didn't have a lot of money then but I wanted to help so we donated a security and fire alarm for the reconstruction of a Young Israel synagogue that had been torched. Only after I started to work on it did I learn that the members couldn't operate the system. My sister designed and built a custom, single-board computer to run the original (pre-Napco) system for us. It had a Jewish calendar algorithm that would be good for 50 years or so. We called it the ESG-1000 (ESG was for "Electronic Shabbos Goy", which everyone loved).
Not long after that Napco and a few other manufacturers came out with panels that could auto-arm / disarm on shedule so we never marketed the ESG. In the meantime though, we became the darlings of the Orthodox community and my little alarm company became a success. Goes to show what a little mitzvah can do, eh?
One thing you might want to do is to write a Shabbos rule that powers down the motion detectors, arms the system and bypasses the Sabbos door just before you leave for shul. The perimeter (less the Shabbos door) would then stay armed all day. After seunset you can disarm it as you please. The rule should not implement if the system is already armed "AWAY" (ie, motion detectors active) on Saturday morning. That would indicate that the family is away from home at the time.
There are lots off other patterned events which I've used for Orthodox families and shuls I protected over the years. Another way to solve the Shabbos / Yom Tov scheduling issue is to attach a programmable, multi-output timer to the system. Set the unit to run a sequence of timed relay triggers whenever it is triggered. Then all you need to do is tie its input trigger to an output of the ELK and tell the ELK to throw that output at a certain time of day on specific calenday days each year.
Most Shabbos patterns are the same -- bypass the Shabbos door for evening prayers, turn off power to motion detectors, arm the system, wait until bedtime, secure the Shabbos door, wait until wake-up time, bypass the Shabbos door again, wait until sunset, end cycle. Most Yom Tov have similar patterns, with the exception of Purim (IIRC) and one or two days during the YK/RH period. By presetting those patterns and off-loading them to a dedicated device you can reduce the programming load on the M1.
Tell the M1 when zone [n1] gets a closure arm the system. When [n1] opens disarm. When [n2] closes kill power to the motions. When [n2] opens, restore power. This kind of programming will give you the same results with maybe 20% of the ELK coding. Since ELK alrready handles sunrise / sunset, all you need to plug into the ELK is the dates. Obviously, there are a few days that are non-standard but those can be handled by the add-on device with very little ELK programming.
The reason I like this approach is it doesn't depend on a PC to maintain operation of the security system.
I'll look forward to it.