[Nut-upsdev] MGE NMC and NutShutdownModule (and other stuff)

[Marco Chiappero]

Arjen de Korte ha scritto:

> Yes, that's what I'm intending to do (and what I have already done for a 
> large part already by the way). This will reduce the latency for changes 
> in the power state to essentially zero. At the same time, we can 
> increase the pollinterval to something like 60+ seconds or so. Receiving 
> an alarm will then trigger a poll of the summary and/or get_object 
> pages, to get all available data.

What about including these ideas and functions into the netxml-ups 
driver maintaining the backward compatibility? We can create a single 
subscription connection, from which we only need to read the 
BelowRemainingCapacityLimit flag (to allow the use of the testing 
button) and the DelayBeforeShutdown value (about the outlet used by the 
system). An alarm message reception can then trigger a summary page scan 
(no need to set timings) while the get_object page, with extended data, 
can be read every "pollinterval" (the user can choose whether to have it 
low and stress the NMC or not).
We can also lower the summary page scans, reading more data from the 
alarms, for example:
- alarm level == 1 -> update data using this alarm and read the summary 
page every "pollinterval"
- alarm level == 2 -> read the summary page immediately
Does it sound reasonable?
Moreover reading the summary page we also know when to start the 
shutdown procedure on every outlet, so we have every kind of information 
we need/want, with just a single subscription.

> As far as I can see, the above value is not client specific. It would 
> have been nice if it was (since that would allow us to easily see that 
> the specific outlet was about to be shutdown), but as far as I can see, 
> this is the global one (not outlet/client specific). What I'm not sure 
> about, is what happens when you sent this via the UPS Controls page for 
> a simulated shutdown event. It could very well be that this would be 
> client specific in that case, but in practice this will be of little use 
> for us. During an actual mains failure, it would only be raised when the 
> batteries are almost flat. Since we would like to shed some loads on the 
> two switchable outlets long before that (the whole point of this 
> exercise), we probably can't use that.

Right. Alarm messages are certainly outlet specific.


Best regards,
Marco