Node-RED block in Snap4City Microservice library node-red-contrib-snap4city-user is "event-driven-my-kpi">
    <p>Shows an output message when the value of the KPI chosen in configuration is modified inside a dashboard, with a widget made in svg.</p>

    <h3>Configuration</h3>
    <dl class="message-properties">
        <dt>when value change
            <span class="property-type">checkbox</span>
        </dt>
        <dd>Selects the event to be observed on the selected KPI. 
            If this checkbox is selected then a message is output only if the KPI value is changed from the previous one. 
            If the checkbox is not selected then a message is output even if a value that is equal to the previous one but with a different timestamp is saved on the KPI. It decides the granularity of the incoming messages.</dd>
    </dl>

    <h3>Outputs</h3>
    <dl class="message-properties">
        <dd> KPI data that has been observed, in particular should change the lastDate and lastValue, for each message</dd>
    </dl>