Feedback to Multiple Panel Philosophies

TurnipTruck

Greetings,

It seems to be widely accepted that it is better to only send feedback to panels that are online and on the specific page that would require the feedback. I have come up with some way of accomplishing this.

However, I have seen no marked improvement over sending feedback to all panels in a DEV array regardless of whether or not they are online and/or on a specific page.

Any thoughts? Thanks.

mpullin

TurnipTruck wrote: »

Greetings,

It seems to be widely accepted that it is better to only send feedback to panels that are online and on the specific page that would require the feedback. I have come up with some way of accomplishing this.

However, I have seen no marked improvement over sending feedback to all panels in a DEV array regardless of whether or not they are online and/or on a specific page.

Any thoughts? Thanks.

If you only send feedback to a panel when that panel is showing the appropriate page, then you AREN'T sending it to panels that are not showing that page. So when a panel accesses that page, any changes to the information displayed on that page have to then be sent to the panel before the user sees the page. This means any information conveyed by your feedback has to be stored in your program, so that it can be recalled and used when a panel accesses said page. This has memory implications. Also, since you have no way to knowing whether the information on the touchpanel on that page is current, you must perform such an update every time the page is accessed regardless of whether it's necessary or not. So even buttons that perform mere page flips need channels and button code. This wouldn't bother the "accomplish all [page flip] navigation with the program" camp, but for those of us that like some separation of interface and program it would be a hassle... the panel is not doing as much of the work as it could.

jweather

The main thing you're accomplishing is reducing network traffic to your panels. If you have a small number of panels and a small amount of traffic, you probably won't notice any difference by sending feedback selectively. If you have a large number of panels and a large amount of traffic, only sending the necessary traffic will speed up the entire system. You should first address high-traffic devices such as iPod docks, music servers, and security systems with real-time point status.

You may notice more of a difference on wireless panels, since the wireless panels have less bandwidth available to them, especially if signal quality is low.

Jeremy

alexanbo

I think it depends on what type of feedback you're sending.

I haven't seen a problem with sending channel on/off feedback to the whole array.

For chatty devices such as Ipods,Music Servers and Security Systems I do limit the feedback they send to only panels that are using/connected to that particular device. This does require sending an initialization when a panel first starts using say an Ipod, but that seems like a worthwhile tradeoff over sending feedback all the time.

DHawthorne

For small jobs, I don't fuss much over it, but once your project gets to a certain critical mass, the network traffic can impact response and reliability considerably, even to the point of crashing the master. It all done under the hood, but every command that goes out to a device also solicits a response. The master keeps an internal queue of all these commands, and it is limited in what it can hold, and processing it is delayed as it waits on some of those responses. You can see this best on startup with a big system (especially if it has Axlink or Phast devices on it); all those queue size messages that settle down once everything is up and running. But if the queue fills completely, it is suspended, effectively shutting down your master.

TurnipTruck

What is the ramification of sending feedback to an offline master, such as a sleeping MVP8400?

DHawthorne

TurnipTruck wrote: »

What is the ramification of sending feedback to an offline master, such as a sleeping MVP8400?

As near as I can tell, it's tiny; it's just that it seems to be cumulative. If you have one master and one panel, I wouldn't even give it a second thought. If you have 20 panels, well, that's another story.