@korttoma Perfect. This is what I came up with in the end, and I have it triggering every minute. I needed the number rounded to the nearest whole number as the thermostat will not display a decimal value for the outside temp.
local CurrentTemp= luup.variable_get("urn:upnp-org:serviceId:TemperatureSensor1","CurrentTemperature", 26)
luup.variable_set("urn:upnp-org:serviceId:LcdText1", "LcdText", string.format("%.0f", CurrentTemp), 365)
Thanks a million.