@user5536 , as you know, you must disarm the system anyway (it will be in Armed Stay mode) in order to open a door or window without triggering your siren. That is of course, unless that door or window is programmed on your DSC as an “Interior Stay/Away” zone (zone Type [05] on the DSC panel) in which case that door or window will only arm in Away Mode and will not provide protection in Stay Mode. You obviously need to access a keypad or keyfob anyway in order to disarm your system if you are exiting out of a type [03] Instant Zone.
Assuming your door is a “normal” type [03] Instant zone, I suppose as you suggested, you CAN make a rule that will need to take into account the time elapsed since a door was opened, with a Required Expression that this would only trigger Stay Arming of the system if the time since opening fell after your normal auto arm time and before any auto arm disarm time you set. Unlike @velvetfoot , I do not have any automatic disarm time set as this time varies tremendously in my household and at any rate, I never want my security system to disarm itself automatically, unless by presence or by my use of my garage door opener or keyfob. I prefer that all disarming of the system for security reasons be done manually. Needless to say, you should also incorporate a “bypass” switch (another Required Expression) such that your Auto Arm/Disarm rule can be bypassed in the event you have a party or other gathering during which you do not want your home automatically armed, LOL.
All the above having been said, imho, the real problem is determining just how much time you wish to have elapsed since door/window opening, before your system auto arms.
Too short a time interval, and you can be left outside with your system re-armed. This is not a problem if you are re-entering through an exit door with an entry delay (so you have time to disarm the system upon re-entry before the siren sounds), but problematic if it is a normal Instant type zone, as the alarm will sound as soon as the door is opened. At any rate, this still means that you will have to go through the hassle of disarming the system, then manually re-arm it (assuming you stay “outside” too long).
Too long a time interval and your house will be unprotected for the entire time interval.
Because of this type of hassle, for convenience, I have set up my DSC/Envisalink system so that it can be armed in Stay mode via voice control. For security reasons, I can only disarm through the keypad, keyfob, or remotely over the internet via Envisalink using a disarm security code. This also “conditions” the family so that they always use the disarm code so they do not forget the code (I found that when I was using primarily presence, they would get lazy and would either forget the manual code or would falsely assume that the system was really armed or disarmed when glitches in presence would occur).
The nice thing about this is that I can arm the house at any time from any location in the house without having to go to a keypad. If you retire to bed early or just want to arm your system prior to your normal auto arm time, you can just verbally arm the system without having to stop at a keypad, fob or pico remote. It is so nice to be able to just say “arm the house in stay mode” from virtually anyplace in the house, especially from your bed. I happen to use Alexa routines to do this (I have also used EchoSpeaks until the heroku problem), but any other voice control system will work as well (Sonos, Ikea etc). My wife happens to like voice control over using dashboards as well for other functions as well, such as emergency lighting, turning off all lights to the house, or any other things that are not handled automatically through automation or motion lighting etc (she likes to tell things what to do rather than having to push buttons, lol).
You can also use a verbal code to disarm the system, however, you are then at risk of someone hearing you enunciate the disarm code.
Anyway, just another consideration when it comes to using Envisalink with DSC. Hope this helps someone and YMMV depending upon your preferences regarding voice control/command.