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
PmgSliderBox object 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 conditions 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 subsystems. The PROMOTIC system can warn the users by visual signals or by sounds and the operators can acknowledge 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
PmaAlarmGroup object that is responsible for alarm evaluation
- how to define which variables and how are to be alarmed
Adding the PmaAlarmGroup object
First of all create a new object of the
PmaAlarmGroup - alarm group type in the
"Boiler1" object
in the editor of Pma objects.
In the open window in the "
Alarm group identifier" configurator enter
Boiler1alr and in the "
Displayed group name" configurator enter název "
Boiler no.1 alarms" too.
There can be multiple PmaAlarmGroup objects present in the application and the group identifier is used in order to tell them apart. That is why each
PmaAlarmGroup object must have a unique group identifier in the framework of the application. Leave the other configurators unaltered.
Once the new
PmaAlarmGroup object is created a new dynamic alarm template also appears. The setup of the alarm template can be verified and modified on the "
Items" tab of the newly created object.
The ways of alarm 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 users about exceeding desired temperature limits, for example if the boiler temperature goes under 5°C (pipeline freezing warning) or if the boiler temperature is greater than 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.