Poll Failure Limit

[Rut Row]

Under "Plugins->Zwave->Controller Management->Z-Wave Networks and Options" there is a checkbox for "Poll Failure Limit"

I can't find this in the help file - what does it do and why would I want to change it?

[AllHailJ]

The roll over help states

'Set this to the number of failures to poll/get level commands that the device can incurr before being set to an Error/Invalid state, which can be used to trigger events so that a notification action can be carried out. Note: This limit is not affected by other command or query transmissions to the node.'

I have never changed mine.

[randy]

Why give a short answer...

There are two ways a device can go to unknown status. A device can go to unknown because it is actually spelled out in the Value/Status pairs. Here is a child node I have made go to Unknown Status



You will note on the Advanced tab that the Value is 254 and the Status is Unknown. Also note that the string is blank



This device has Unknown as a Status and 254 as a Value defined



The other way a device can go to Unknown is by being set to an Invalid or Error state. This flag is defined in the device, but is not viewable on the device. Here I have created a Virtual Device and set that flag to be true.



Note that the button shows the Status as Closed and the Advanced tab reflects the Value as 0 and the Status as closed. The String remains blank


I can change the status to Open, but the device still shows as Unknown





This is because I set the device as Invalid with an immediate script call

&hs.DeviceInvalidValue(6960) = True

the Invalid state can be cleared by setting that flag to false

&hs.DeviceInvalidValue(6960) = False



Whenever a Z-Wave Device is queried through a poll or given a command it responds. The setting on the Z-Wave Controller menu determines how many times the device can fail to respond to a poll before it is set to Invalid. The default setting is 2, meaning that on the third successive failure to respond to a poll, the Device will be set to Invalid. I believe that failed commands will set that flag immediately and will not be affected by this setting.

If you have a node that is slow to respond, or you have a sluggish network and it is polled too frequently, you may see these errors. In that case it is always best to fix the polling rate or the network, but you can set this number higher to give the device more failures to respond before the flag is set. I believe there is an internal counter that increments with each failed poll and is reset with each successful poll. I have never needed to move mine from the default of 2.

A successful response from a command or a successful response from a poll will clear the flag. If you want to clear the flag manually it can be done with an immediate script as shown above. I also created a handy little Event and Virtual Device that will clear it. The virtual device has a text entry box



and I set it to accept whole numbers from 1-9999.



The Event just looks for a change in the Value of that Device and uses that Value as the RefID of the device where I want to clear that flag.



Hope this helps!