From the example provided in the last section, it is very easy to implement an analytical function to check the signals and to apply a digital twin. The following function defines a simple excursion monitoring function and evaluates the value of data streaming:

const digitalTwin = {};
digitalTwin['signal1'] = {upperLimit: 40, lowerLimit: 10};

exports.helloPubSub = (event, callback) => {
 const pubsubMessage = event.data;

 const str = Buffer.from(pubsubMessage.data, 'base64').toString();
 console.log(str);
 const data= str.split(',');
 console.log({
 'device': data[0],
 'tag': data[1],
 'value': data[2],
 'ts': data[3], 
 'quality': data[4]
});

const deviceId=data[0];
const tag=data[1];
const value=data[2];
const timestamp = data[3];
const quality = data[4];

var dt = digitalTwin[tag];
if ((value > dt.upperLimit || value <dt.lowerLimit) && (quality=='GOOD'))
{
console.log(`excursion on ${tag} : ${value}`);
}
callback();
};

To deploy the current function, we can follow the same procedure that we carried out previously:

1. From the left-hand menu of the homepage, click on Cloud Functions, then Create function, and add the following information:

2. Finally, click on the Save button

To check whether our first basic analytics have executed successfully, run the device emulator again and check the function log.