12/3/2020 6:19 PM | |
Joined: 3/14/2008 Last visit: 8/22/2024 Posts: 2089 Rating:
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Hi, There are multiple ways to approach this. Both involve work on chart level. One is by using the alarm enables (like PV_AH_En) on the pressure transmitter and connect those to the pump running signal. Maybe with a timer in between. Another is smart alarm hiding, which basically involves the use of plant states like production, cleaning etc and based on the states enabling/disabling alarms, but this option will take you much more time, but then it is project ready for other signals as well. |
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12/4/2020 2:47 AM | |
Joined: 9/9/2015 Last visit: 8/14/2024 Posts: 727 Rating:
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Dear GBMartin, Yes, you need to do it from the chart level. Let me share my experience in this domain. 1. First step is to get proper documentation from end-user (System integrator can assist when job scope is defined during the tender stage). Basic planning will be done on the greenfield or brownfield system. There must be a document to define an alarm philosophy and objectives of the alarm system and the processes to meet those objectives. The aim is to reduce the number of alarms and surface only meaningful alarm that needs operator attention. During this phase, they will need to identify all the tag number/logic and write down in alarm system requirement specification (ASRS) or they can compile it in system functional description. 2. the second phase is to identify all the potential alarms (By end-users)(System integrator can assist when job scope is defined during tender stage). The identification methods could be from process hazard analysis, safety requirement specification, incident investigation, operation experience, P&ID development and etc. For example, based on experience, we know that when the pump is not running, the line pressure is not important. It should not be triggered by an alarm when the line instruments are doing simulation. Pressure instrument, flow instrument will be assessed one by one and control via alarm management logic. For example, when the pump run, start a timer for 30seconds then trigger the enable flow instruments alarm activation. The noise, Deadband , alarm delay-off timer will need to be defined for flow, level, pressure, temperature and analyser equipment. Warning /Alarm should not be used for normal operation control. Sometimes, people might use warning to trigger a logic to run. The warning message will eventually make the operator feel like "It is normal". This is similar to fire drill alarm, when it appears too frequent, people will ignore it. 3. Rationalization, detailed design - to be done by end-users. (System integrator can assist when job scope is defined during the tender stage) 4. Implementation and testing stage - after you get the alarm management list with equipment and logic, then you can program your system using smart alarm hiding in PCS 7. I recommend smart alarm hiding. For the implementation of alarm management logic using PV_AX_En, when the alarm is disabled, it disappears from the faceplate and function block parameters which makes it extremely difficult to audit/verify. If an audit is carried out on the alarm settings, an export of the system showing all configured alarm will actually show all disabled. The alarm does not exist/have not been configured. So I recommend using Smart alarm hiding feature in PCS 7, use standard siemens STRep / StateRep function block to realize the alarm logic. The function block allows for the alarm to remain fully configured and auditable. If the alarm condition appears while the alarm is deemed irrelevant, the STRep block moves the alarm message straight to journal and set it as 'hidden'. These hidden alarm does not annunciate to the operator and thus does not require any intervention from the operator. 5. Next is an operation, maintenance, monitoring and assessment, management of change and audit phase. This is normally initiate/done by end-user. Hope this is useful for you. |
Last edited by: JazTai at: 12/04/2020 02:51:17Please give me 5 stars Rating if my post is helpful for you. :) |
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12/4/2020 11:39 AM | |
Posts: 6 Rating:
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Hi JazTai Thankyou so much for taking the time to reply to my request its very much appreciatted. Thankyou very much for the information and sharing your experience. If I am honest I am still quite green to the Siemens PCS7 therefore I would need to research more about this smart alarming because if I am honest I didnt even know it existed! I will certainly have a look at this STREP block and see if I can have a go at it. Thanks again
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12/7/2020 9:46 AM | |
Joined: 5/3/2017 Last visit: 5/21/2024 Posts: 673 Rating:
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Hi GBMartin, if you are looking for more information about Smart Alarm Hiding, please have a look at the application example Alarm management in SIMATIC PCS 7 – Smart Alarm Hiding. There you can find detailed information about the implementation and use of Smart Alarm Hiding. With regards |
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