The Research Of Alarm Logic Model

The thesis could be finished successfully with the guide, supports andhelps of teacher Mr. Tian Xiaojian, and the author greatly appreciates hisefforts hereto.The thesis is basic on the experience of the writer's teaching andpractice over years. The inconvenience and more unnecessary work load arederived from the complexity and variety of the programming andconfiguration in automatic control system engineering. The primary researchfor alarm programming and configuration is described in this thesis and somealarm logic models are also discussed here. The writer hopes that the thesiscan take helps to some readers. If so, the writer fells a little gratified.In the thesis, one basic alarm logic model is described at first on thebasis of the main alarm essentials in the automatic control systemengineering, then are some varieties of the basic alarm logic model given outaccording to the combination of the basic alarm logic model and actualdemands in the automatic control system engineering. The detailed logicanalyses for these varieties are figured out, so that readers should be able tounderstand the key conceptions of the thesis.The logic analyses are done under the following aspects. ① The logicanalysis without alarms. ② The logic analysis with alarms unacknowledged.③ The logic analysis with alarms acknowledged. ④ The logic analysis afteralarms disappeared. ⑤ The logic analysis of the test signal for alarm lamps.The logic analyses of alarm lamps and horns are described individually atdetails.The main alarm essentials in the automatic control system engineeringare as below. ① The alarms are divided into priorities depending on theimportance. When alarms occur, the alarm lamps blink with differentfrequencies and the alarm horn sounds with different tones. ② When alarmsoccur, the alarm lamps blink and the alarm horn sounds. ③ After the alarmsdisappeared, the alarm lamps go out and the alarm horn is mute. ④ After thealarms acknowledged, the alarm lamps stop blinking and lamplight becomesstable, and the alarm horn becomes mute. ⑤ One pushbutton for alarm lamptest is utilized to check whether the alarm lamps work well or not.The functions of the alarm logic models are described respectively asbelow.Basic Alarm Logic Model -When no alarm exists, the alarm lampskeep died and the horn is mute. When an alarm occurs, the alarm lamps blinkwith different frequencies and the alarm horn sounds with different tonesaccording to the importance of the alarm. After the alarm was acknowledgedby pressing the alarm acknowledgement pushbutton, the alarm lamps stopblinking, but don't go out and lamplight becomes stable, thereby the relatedpeople are always reminded that an alarm came into being and wasacknowledged, but hasn't been remedied yet, but the alarm horn becomesmute. The alarm lamps return to be died and the horn return to be mute ifonly the alarm disappeared in despite of the alarm acknowledged or not. Sothe alarm logic returns to the status without alarms and waits for the nextalarm coming. As long as the test pushbutton for alarm lamps is pressed atany time, all alarm lamps will be lighted and the horn will sound so that thelamps and horn can be checked whether they work well or not.Variety 1 of Alarm Logic Model -When no alarm exists, the alarmlamps keep died and the horn is mute. When an alarm occurs, the alarmlamps blink with different frequencies and the alarm horn sounds withdifferent tones according to the importance of the alarm. After the alarm wasacknowledged by pressing the alarm acknowledgement pushbutton, the alarmlamps stop blinking, but don't go out and lamplight becomes stable, therebythe related people are always reminded that an alarm came into being andwas acknowledged, but hasn't been remedied yet, but the alarm hornbecomes mute. If the alarm disappeared without the contrived interventionbefore the alarm acknowledged, the alarm lamps keep blinking and the hornkeep sounding until the alarm acknowledgement pushbutton is pressed. Thealarm lamps return to be died and the horn return to be mute after the alarm isacknowledged, so the alarm logic returns to the status without alarms andwaits for the next alarm coming. As long as the test pushbutton for alarmlamps is pressed at any time, all alarm lamps will be lighted and the horn willsound so that the lamps and horn can be checked whether they work well ornot.Variety 2 of Alarm Logic Model -When no alarm exists, the alarmlamps keep died and the horn is mute. When an alarm occurs, the alarmlamps blink with different frequencies and the alarm horn sounds withdifferent tones according to the importance of the alarm. If the alarmdisappeared without the contrived intervention before the alarmacknowledged, the alarm lamps keep blinking and the horn keep soundinguntil the alarm acknowledgement pushbutton is pressed. The alarm lampskeep blinking, but the horn becomes mute after the alarm is acknowledgedfor the first time. The alarm lamps go out and the horn keeps mute after thealarm is acknowledged for the second time, so the alarm logic returns to thestatus without alarms and waits for the next alarm coming. As long as the testpushbutton for alarm lamps is pressed at any time, all alarm lamps will belighted and the horn will sound so that the lamps and horn can be checkedwhether they work well or not.Variety 3 of Alarm Logic Model -When no alarm exists, the alarmlamps keep died and the horn is mute. When an alarm occurs, the alarmlamps blink with different frequencies and the alarm horn sounds withdifferent tones according to the importance of the alarm. If the alarmdisappeared without the contrived intervention before the alarmacknowledged, the alarm lamps return to be died and the horn return to bemute. After the alarm is acknowledged, the alarm lamps return to be died andthe horn return to be mute, but a period of time elapses, the alarm lamps startto blink again and the horn start to sound again too, thereby the relatedpeople are always reminded that an alarm used to come into being and stillexists. Even if other alarms come into being, the alarm lamps keep died andthe alarm horn keeps mute during the period of time until the period of timeelapses. As long as the test pushbutton for alarm lamps is pressed at any time,all alarm lamps will be lighted and the horn will sound so that the lamps andhorn can be checked whether they work well or not.Control engineers have to select an alarm logic model to use in theprogramming and configuration according to the actual demands ofcustomers. The above 4 alarm models perhaps don't meet the alarmrequirements of all customers. Control engineers are able to figure outvarious alarm logic models in order to meet the actual alarm requirements ofcustomers on the basis of these 4 models so that the control systemengineering be accomplished successfully.Usage of alarm logic models makes the total logic program smaller,cycle time shorter and data update faster, thus the precision and rapidness ofplant control will be improved, so the disadvantages due to larger logicprograms will be avoided. On another aspect, usage of alarm logic modelsmakes the logic programs simpler and cleaner, and makes other controlengineers understand the logic programs more easily so that the work willproceed on more fluently.