Here is example of Rules API solution to copy the temperature measurement to number field for calculations ( for those who want to use Rules API )
{
"name": "Every 15 min Temp copy to Number Field 2",
"actions": [
{
"every": {
"interval": {
"value": {
"integer": 15
},
"unit": "Minute"
},
"actions": [
{
"command": {
"devices": [
"id number field device"
],
"commands": [
{
"component": "main",
"capability": "legendabsolute60149.numberFieldTwo",
"command": "setNumberFieldTwo",
"arguments": [
{
"device": {
"devices": [
"id temperature measurement device"
],
"component": "main",
"capability": "temperatureMeasurement",
"attribute": "temperature"
}
}
]
}
]
}
}
]
}
}
]
}