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HOW TO SELECT A CPU FOR PROCESS PLANT

Created by: Uppi at: 7/28/2010 8:02 AM (15 Replies)

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9/1/2010 12:26 PM	Rate (0)
Uppi Posts: 17 Rating: (0)	Thank u mr nick and pratap i understoodUrfirstexplanation.here i tried tocalculate the remaining PO's as perUrcalculation but it is not matching inUrdocument ? Can u please help in this issue and what is the importance of SFC here and U specified that PO is monitoring point and if i am not monitor a motor or PID is it a PO?
Uppi Posts: 17 Rating: (0)
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9/1/2010 3:52 PM	Rate (0)
NickM Posts: 25 Rating: (9)	VEERABABU, I am not sure what you mean by the remaining PO count doesn't match in my post, but let me try to answer your question this way. With your device and I/O count, there wasn't enough information to know exactly how many POs your system will need. I had to make a rough estimate, and so I assumed that the extra AIs and DIs were monitor points. Monitor points are information that your system may require or you may want to display on an HMI, such as pressures, temperatures, and flows. These can come from instrumentation (AIs), or from switches (DIs). With your extra AOs and DOs, again I did not know enough to determine exactly what the PO count should be, so I assumed that each extra AO and DO that did not come from a motor, valve, PID, etc. was a PO. I then added 20% (I multiplied my total by 1.2) to make allowances for any mistakes in my estimate. My understanding is that anything that will generate an alarm counts as a PO in the Automation System (AS).Each SFC also counts as a PO in the AS. For example, if I am monitoring a pressure, and it has a level where it is considered to be high, and this creates an alarm on my system, then this is a PO in the AS. And please keep in mind that a PO in the AS is different from a PO in the Operator Station (OS)!!! I hope this helps you to understand where my numbers came from. If there is something specific that you don't understand, then please let me know. Regards, Nick
NickM Posts: 25 Rating: (9)
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9/3/2010 9:04 AM	Rate (1)
Gunners Posts: 130 Rating: (18)	Dear Veerababu/Nick, See its as simple as this......What is this PO thing? Take for example a Motor Or a Pump Block , now for this kind of block you have the following basic parameters to monitor....like 1) Start/Stop 2) Trip 3) Fail to start 4) Fail to Stop 5) Running And Faceplates + Logic for all the above parameters. All these signals for 1 motor will be 1 PO........ This is how you gotto count the no.of PO's..... Hope this helps.... regards,
Gunners Posts: 130 Rating: (18)
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This contribution was helpful to 3 thankful Users NickM Arunraje ect_09

9/8/2010 6:54 AM	Rate (0)
Uppi Posts: 17 Rating: (0)	Thank you two and i understood PO concept my question is if i don't monitor a motor/valve from Wincc.... is it a PO? Please can u answer me?
Uppi Posts: 17 Rating: (0)
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9/8/2010 6:30 PM	Rate (0)
NickM Posts: 25 Rating: (9)	VEERABABU, To answer your question, if you don't monitor a motor or valve in WinCC, but you have the motor or valve block in the AS, then it is still a PO. The reason why is there are alarms that come with the motorandvalve blocks. Regards, Nick
NickM Posts: 25 Rating: (9)
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This contribution was helpful to 1 thankful Users ect_09

5/8/2012 8:33 AM	Rate (0)
Aniket S Dange Posts: 22 Rating: (3)	Helpful description... thank you..
Aniket S Dange Posts: 22 Rating: (3)
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