Rules to only fire when its :00 or :30

Setup, Configuration and Use Scripts & Rules
14

If you take away the requirement that the alert come exactly at 00 and 30 and make your requirement that it only report every 30 minutes it is below the threshold it becomes much simpler. I’ll use Design Pattern: Expire Binding Based Timers and Design Pattern: Separation of Behaviors.

rule "PVisland Voltage below 23V Alert - Notification"
when
    Item PVislandVolt changed
then
    // NULL isn't a value we can use in this rule
    if(PVislandVolt.state == NULL) return;

    // If the Timer is already running we have nothing to do
    if(PVislandVolt_Timer.state == ON) return;

    // Voltage is low, alert
    if(PVislandVolt.state < 23) {
        aAlert.sendCommand("PVisland | Battery Voltage Level Alert | " + PVislandVolt.state + "V", "--EOM--")
        PVislandVolt_Timer.sendCommand(ON)
    }

    // Voltage is back above threshold, cancel alerts
    else {
        PVislandVolt_Timer.postUpdate(OFF)
    }
end

rule "PVislandVol timer expired"
when
    Item PVislandVolt_Timer received command OFF
then
    // No more alerts if the voltage goes above the threshold
    if(PVislandVolt.state == NULL || PVislandVolt.state >= 23) return;

    // alert and reschedule the Timer for another 30 minutes while it remains below threshold
    aAlert.sendCommand("PVisland | Battery Voltage Level Alert | " + PVislandVolt.state + "V", "--EOM--")
    PVislandVolt_Timer.sendCommand(ON)
end

If you only want the one alert when it first goes below the threshold and not get repeats, which you stated is your ultimate goal, then Scott already provided that answer in post 4.

As you can see, minor changes in your requirements can result in drastically different solutions. And all things considered, implementing your ultimate goal is actually far easier than your stated compromise solution.

1 Like