In the previous chapters you have created three variables in the "BoilerPlant/Boiler1/Data" object, namely "Temperature", "Power" and "Status". You write a number generated in the script of the timer "Emul" every second into the "Temperature" object. You change and influence the value of the power by moving the slider of the PmiSliderPane item that you've placed in the window named "Panel".

In real applications it is almost always requested to make them warn the user(s) once some non-standard conditiond accure in the monitored technology (e.g. exceeding the defined temperature, sensor malfunction, communication error, etc.). These requirements are addressed in the PROMOTIC system by using the alarm and event subsystems. PROMOTIC can warn the operators by visual signals or by sounds and the operators can confirm such alarms (i.e. confirm the alarm has been acknowledged). All alarms are logged and can be viewed afterwards.

In the following chapters you will learn:
- how to add and configure the PmAlarmEvent object that is responsible for alarm evaluation
- how to define which variables and how are to be alarmed

Adding the PmAlarmEvent object

First of all open the application editor and create a new object of the PmAlarmEvent - alarm group type in the "Boiler1" object. In the open window of the "The name of created object" configurator enter the name "alarms" and in the "Alarm group identifier" configurator enter "alarms" too. There can be multiple PmAlarmEvent objects present in the application and the group identifier is used in order to tell them apart. That is why each PmAlarmEvent object must have a unique group identifier in the framework of the application. Leave the other configurators unaltered.

Once the new PmAlarmEvent object is created a new dynamic alarm template also appears. The setup of the alarm template can be verified and modified by going to the "List" page of the newly created object.

The ways of alarming the variables

The value of each variable can be alarmed basically by two ways - analog alarm and binary alarm.

The analog alarm is suitable for example for boiler temperature, where it is required to inform the operators about exceeding desired temperature limits, for example if the boiler temperature goes under 5°C (pipes freezing warning) or if the boiler temperature goes beyond 95°C (high temperature/pressure waring).

The binary alarm is usually used for logical variables, for example boiler on/off, or status variables where each bit holds the information about the status of the current device. For example bit 0 - boiler on/off, bit 1 - manual/automatic mode, bit 2 - boiler malfunction, etc.

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