Use the Change of Value KPI

the change of value kpi displays the complete message payload when the current value differs from the previous value if there is no substantial change, no output is displayed user scenario review the following scenario for the change of value kpi processor function then, using an input processor, you will simulate plc data and use this kpi to detect a change of value in the input field in an industrial setting, the change of value kpi is used to monitor the voltage levels in an electrical grid the input processor continuously collects voltage data and feeds it to the change of value kpi processor the kpi triggers an output when there is a substantial change in voltage, alerting the operators to potential issues otherwise, if things are normal, no output is expected it allows the engineers to promptly respond to voltage fluctuations, preventing equipment damage and outages step 1 add a device follow the steps to connect a device docid\ rfvijdxz7dbad8mwbisma and configure the following parameters device type simulator driver name generator enable alias topics select the checkbox step 2 add tags after connecting the device, add the following tag see add tags docid\ ioanzd2awqnkuppgee3eh to learn more tag 1 voltage name select s random value generator value type select float64 polling interval enter 1 tag name enter voltage min value enter 99 max value enter 103 step 3 create analytics flow you can now create the analytics flows using data from the device and tag you previously created to create an analytics flow with the change of value processor function in manufacturing connect edge, navigate to analytics on the analytics canvas, click add processor the create a processor dialog box displays select datahub subscribe in the topic field, click the search icon, select the device you previously created, and then select the alias topic for the voltage tag click save click add processor again and select the change of value processor the following information defines this function map field name enter the field you want to observe like value or timestamp , depending entirely on the input message you are sending to this kpi delta of tolerance enter a delta of 1 if you want to allow ignoring a change of +/ 1 from your previous value if you enter delta as 0 , even the smallest change will be detected by this kpi time interval if the tag publishes at the expected interval, it is better to disable this timer by entering 0 in the field click save connect the datahub subscribe processor (tag voltage ) to the change of value processor with a wire and use the events connection on the analytics canvas, click save the configured analytics flows should look like the following step 4 view output of processor click the view icon in the change of value processor to view the output values the output displays the message payload when the value field is +/ 1 from your previous value