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Enthalpy calculation in S7

Created by: Manju at: 11/17/2008 9:12 AM (9 Replies)

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11/17/2008 9:12 AM	Rate (0)
Manju Posts: 39 Rating: (0)	Dear Forum, We have given a S7-300 system for a Steam Turbine Auxiliary Control. User needs Enthalpy of steam to be calculated based on Temperature and Pressure. Is there any standard block for Enthalpy calculation in S7 ? Or can anybody help us with a block or an algorithm for this particular calculation. Regards, Manju
Manju Posts: 39 Rating: (0)
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11/17/2008 10:11 AM	Rate (0)
Ayman Elotaify Platinum Expert Joined: 5/28/2008 Last visit: 11/6/2024 Posts: 4516 Rating: (839)	Manju Dear Forum, We have given a S7-300 system for a Steam Turbine Auxiliary Control. User needs Enthalpy of steam to be calculated based on Temperature and Pressure. Is there any standard block for Enthalpy calculation in S7 ? Or can anybody help us with a block or an algorithm for this particular calculation. Regards, Manju Dear Manju, Actually there are two ways of thinking for your problem. 1. You can easily down load the chart from the internet and think if you can build a polynomial equation for calculation of Enthalpy. I know it won't be easy! 2. If you can reach to a tabels for the enthalpy from the internet or you can make these tabels from the charts.Then, put these values in data blocks; let's say you will have many data blocks and each data block are for certain pressure; and so on. I have a free software for calculating enthalpy. you can download it free from the internet: http://www.et.web.mek.dtu.dk/Coolpack/Files/RefUtil.exe Regards.
	Ayman Elotaify
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11/17/2008 10:39 AM	Rate (0)
Manju Posts: 39 Rating: (0)	Dear Ayman Elotaify, We went through the net and there are too many documents talking about enthalpy. Is there any standard method for calculating enthalpy of steam? We found too many steam tables and don't know which one to consider and unfortunately our client also doesn't know. Now he's depending on us to perform this calculation. Regards, Manju
Manju Posts: 39 Rating: (0)
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11/17/2008 5:12 PM	Rate (0)
Gebhardt Karl Platinum Member Joined: 7/16/2006 Last visit: 1/2/2024 Posts: 1502 Rating: (176)	Check here www.oscat.lib Free with Sorcecode.
	Karl
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11/18/2008 6:34 AM	Rate (0)
Manju Posts: 39 Rating: (0)	Hi Karl, I checked out this link www.oscat.lib but it doesn't work. Is there anything wrong with the link? Regards, Manju
Manju Posts: 39 Rating: (0)
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11/18/2008 8:01 AM	Rate (0)
nemblej Posts: 34 Rating: (3)	I think the proper link would be http://www.oscat.de/ You'll find an open source library there (for Siemens and other PLCs too). I haven't checked if it contains the calculations you need though.
nemblej Posts: 34 Rating: (3)
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11/18/2008 8:07 PM	Rate (0)
Gebhardt Karl Platinum Member Joined: 7/16/2006 Last visit: 1/2/2024 Posts: 1502 Rating: (176)	Sorry, i mean www.oscat.de Here are FCs for Calculate - "Water_density" -"Water_enthalpy" - "Air_density" - "Air_enthalpy" In the Source you can read Information in English. If give a Farum for the OSCAT-LIB to.
	Karl
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5/28/2023 10:37 AM	Rate (0)
tangke1993 Joined: 12/26/2022 Last visit: 5/28/2023 Posts: 2 Rating: (0)	You need to write the IF-97 Equation into PLC using SCL language. Attachment 7994ce0068aeb3af466ff1235a95f91.png (429 Downloads)

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5/28/2023 10:42 AM	Rate (0)
tangke1993 Joined: 12/26/2022 Last visit: 5/28/2023 Posts: 2 Rating: (0)	You can contact me through email [snip] for more detailed info. This attachment show the steam calculation block with input P and T. And it gives out multiple results as well as steam state.(saturated or superheated) Attachment superheat.png (403 Downloads)
	Last edited by: Jen_Moderator at: 05/30/2023 07:05:17 E-mail address removed, doesn't comply with forum terms.
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6/12/2023 10:02 AM	Rate (0)
AutoGen_8077147 Member Joined: 3/14/2022 Last visit: 8/30/2024 Posts: 1 Rating: (0)	Where to find this FB steam?

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