How can I add a delay to Lua script

Developer's Corner General Dev Discussions
1

Im just starting our on LUA coding. I want to measure the watts being consumed after I power up a device

If I use the following code

local watts = luup.variable_get( “urn:micasaverde-com:serviceId:EnergyMetering1”, “Watts”, device)

When I look at the variable watts it returns ‘undefined’. Do I need to wait a few seconds after power up before measuring the power consumption? If so how do I add a delay of a few seconds.

Many thanks

2

You probably have the wrong device id … or you entered it as a string … it needs to be a number.
You should get the same value you see on the Advanced Tab → Variables for that device.

3

Thank you

I defined device as

local device = 5

I checked and the ID is correct. In advance>variables watts is shown as 100

4

Is your statement in your LUA startup code? I have noticed that when that code executes, the Vera environment is not completely set up.

What I did to solve this is to have the startup code run a “Start Up” scene (the run statement technically just schedules that scene). When the Vera/LUA engine is all ready to go, the “Start Up” scene will then get run. You could put your code in that scene.

5

Its part of a scene that is triggered when device ID is switched on. I agree with you that it may be too soon. This is why I thought of m adding a delay after switch on before taking the measurement of Watts.

I’ll give your scheduling idea a go.

In the meantime, how do I add a delay in LUA?

6

I have got it working. I used call_delay to provide some time for the device to power up and initialise itself. Now it returns the correct watts measurement every time.

[code]local device = 5

luup.call_delay( ‘WATTS’, 60)

function WATTS()
local watts = luup.variable_get( “urn:micasaverde-com:serviceId:EnergyMetering1”, “Watts”, device)
end[/code]

I saw an extension called ‘is_ready’. Would this function wait until a device has initialised after power up before returning measurements like ‘Watts’?

If so how do I use this variable. I had trouble with it.

I tried

if (luup.is_ready(deviceID) then -- do something end

This didnt seem t work. Any help on the proper use of this extension please.

7

I do not know the answer to your is_ready question, but you do realize that there is a syntax error: Missing closing parenthesis.

if (luup.is_ready(deviceID)) then
-- do something
end
8

[quote=“aa6vh, post:7, topic:193939”]I do not know the answer to your is_ready question, but you do realize that there is a syntax error: Missing closing parenthesis.

if (luup.is_ready(deviceID)) then -- do something end [/quote]

Yes, I saw that. that was an error as I typed it out and didnt cut and paste.

Does anyone know how to use the is_ready function?

Many thanks