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| 9/11/2011 8:29 PM | |
Joined: 3/21/2006 Last visit: 3/30/2025 Posts: 10239 Rating:
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Hello, Please attach here your sample project. best regards, Hristo MIhalev |
| 9/16/2011 10:10 AM | |
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Posts: 103 Rating:
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hi.... umencho i m here sending uthe my project take a lookon it i want to tell u that when i try to run this in plc its lmn ,error value do not get any change, pls find the attachment Attachmenttest_pid.zip (608 Downloads) |
| 9/16/2011 11:00 AM | |
Joined: 1/28/2009 Last visit: 9/15/2025 Posts: 6875 Rating:
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Dear veer Please refer to the following Tag in which 2 threads clustered. Those threads are about sample example projects to handle FB41. Standard PID Package - FB41 Samples The following points are strange for me: 1- small integration time of 100ms 2- using the whole block as a P controller by disabling I and D parts You have constant error signal because you are using a P controller in which error=P*(SP-PV) Also check the attachment for the online help of the function. Best regards Attachment1.pdf (1214 Downloads) |
| 9/16/2011 2:04 PM | |
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Posts: 103 Rating:
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hi... marc if i didnt define pv_per this means not that i dont get lmn and i wanna tell u that this program run proprly in plc sim so why dont same action in actual plc. and also take look on this atttachment which shows area length error AttachmentDiagnose.zip (497 Downloads) |
| 9/16/2011 3:36 PM | |
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Joined: 1/28/2009 Last visit: 9/15/2025 Posts: 6875 Rating:
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Hello again Please Note, you have problem in other FBs inside your project.To check FB41,just check the following modified version of your program.Besides, you need to change SP_INT,I also include it in your project,add I part to your algorithm and change the integration time to 10s. Best regards AttachmentMODIFIED.zip (594 Downloads) |
Last edited by: hdhosseini at: 9/16/2011 3:38 PM |
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| 9/17/2011 9:24 PM | |
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Posts: 103 Rating:
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hello sir , as u told i changed set point and also bypassed the algorithm by putting it to manual mode and set manual value but still there is no change in error and lmn value, as i told u earlier when i simulate this program in plcsim the error and lmn value changes but not with plc i m having the error when i run it "area length error when reading" i m also attaching the diagnostic buffer information pls have look on it thanks AttachmentDiagnose.zip (303 Downloads) |
| 10/23/2011 7:35 PM | |
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Joined: 1/28/2009 Last visit: 9/15/2025 Posts: 6875 Rating:
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Dear veer Please check binary status of COM_RST in FB41 and the attachment as a sample variable table.Note, if this variable is activated ,algorithm is totally bypassed .No error calculation and no LMN generation! Best regards |
| 10/24/2011 6:24 AM | |
Joined: 10/7/2005 Last visit: 9/14/2025 Posts: 3049 Rating:
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Hello veer all I can offer is a couple questions: 1.) You did download (S)FB41's IDB, didn't you? 2.) Are you using FB41 or SFB41? The Compact CPU's have SFB41 inbuilt which would be more efficient to use (I believe FB41 should work in your 313-C CPU too, I haven;ttried it though and it would be wasteful to use it). Chapter 7 of the SIMATIC S7-300 CPU 31xC Technological Functions has more on SFB41? I hope this helps |
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