Why when using an input value, it returns "null"?

The code snippets:

preferences {
    input name: "wakeUpInterval", type: "number", title: "Wake Up Interval", description: "Enter Wake Up Interval", required: true, displayDuringSetup: true, defaultValue: 24

    valueTile("wakeUp", "device.wUI", inactiveLabel: false, decoration: "flat") {
		state "wakeUp", label:"Wake Up Interval:" + wakeUpInterval , unit:""

It should be straight-forward usage and I don’t know why the variable “wakeUpInterval” returns “null” when used in the label.
What am I missing?

For example, when the gateway is setting the device’s Wake Up Interval, I use:

    result << response(zwave.wakeUpV1.wakeUpIntervalSet(seconds:3600*wakeUpInterval, nodeid:zwaveHubNodeId)) 

and “wakeUpInterval” is not null - it holds the number value.

What is the problem with the tile’s label?

I’m pretty sure you can’t display a setting in a tile directly.

It looks like you created the attribute “wUI” for it, so use the sendevent command in the updated method to set the attribute value to the setting value.

Display that value in the tile using:

label: '${currentValue}'


Thank you!!!
I tried with sendEvent before, but I was sending it to the state “wakeUp”, not to the attribute - noobish mistake.
All good now.