Basically, the implementation is a combination of:

- Load switching (0-off, 1-on)

- Demand limiting (e.g. via STS token) (demand limiting happens via a combination of a setting between 0 and 1, and the Connection Size on a meter, and e.g. generating the STS token to limit the demand)

- Load/Demand Scheduling (via Calendar, on a 'Time of Use ID') - potential pre-programming of switching schedules on devices if the device supports it; otherwise through tasks that are scheduled, in other words hundreds of devices can be switched at once, potentially. As the schedule changes, it triggers devices entities to reprogram devices. The 'programming of schedules into devices' hook typically also cause the scheduling of Tasks in the Acquisition queue, either to do the switching itself, or to reprogram the devices when the programmed schedule is about to go off-spec. If devices can only partially reprogram, it schedules a new task to reprogram well before the schedules would diverge. (the result of a TOUID is essentially: put in a time of day, and get a value from 0 to 1, including 0 for off and 1 for on, but also potentially just limiting the demand limit)

- There are a number of different kinds of Calendars. The one everyone @ pnpscada has come to know and love for a long time already is the Time of Use Calendar, but there are others. E.g. the Daylight calendar, which switches on at Night, and takes GPS co-ordinates as some of its parameters when you create it.

- You can 'control' a Load from a combination of 'controllers', and specify Boolean algebra gates, e.g. OR, AND etc. For instance you can have one schedule for daylight and another for business hours, and specify the Load to do AND, so for instance you only switch on the lights when it is business hours during daylight.

- Real time demand limiting or switching would happen via some kind of a 'Calendar' that switches its schedule, almost as though a user is editing and validating it periodically.
- In future, we might also interface to spot pricing tariffs through a similar method, to edit actual historically kept tariffs/tariff periods, but that is only a glint in marinus's eye at the moment.... :-)