Entering the Service tab within the Hub's own settings menu, we can find a number of parameters.
This parameter means that, after having confirmed the loss of connection with the Hub, the cloud sends a Polling failure, but will wait 30 seconds before communicating this loss of connection to those connected to the Hub (basic users, PRO and CRA users).
This parameter regulates the determination of the polling failure.
The AJAX Hub will always send 3 pings of Polling, and in this section we can set the time interval we want to have between each ping to the cloud. If after those 3 pings there has been no communication, the Polling failure is determined.
Then, if we set 30 seconds of alarm delay in the first parameter described, the cloud will do the following:
- will send 3 pings every 10 seconds to confirm the loss of connection (as set in the second parameter)
- after the last ping that has not returned, will wait another 30 seconds before sending the notification of lost connection (as set in the first parameter). If in that time the cloud receives ping again, it will NOT send the Polling failure notification.
SUMMARY: How long after the effective loss of connection will we receive a notification about it?
With the parameters set, the answer is: (10 x 3) + (30) = 60 seconds
The reader will have already understood that in the "Service" tab the order of these settings is as if inverted, i.e. the first one that appears is the delay time after the loss of the pings, while the second parameter that appears is related to the time between the pings --> chronologically these times are applied in reverse with respect to their order of appearance in the menu we have just analysed.
Knowing all this we want to differentiate this notification (object of the article) and the event E602; the latter is the periodic event of KeepAlive of the Hub and is configured in another section:
The periodic test describes the state of life of the Hub itself, and is of interest only to the CRA.
Instead, the failed Polling signal describes the status of the connection between the Hub and the cloud, and eventually produces a notification that reaches both the apps and the CRA, but for the CRA it is purely informative since by standard what is usually looked at is the Hub's own event E602.