4/22/2017 12:02 PM | |
Joined: 9/27/2006 Last visit: 8/23/2024 Posts: 12279 Rating:
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Hello DrTroop; I always find it fascinating when someone starts his/her thread with a claim that a standard and much-used function provided by a manufacturer (in this case Siemens, but I have seen such thread titles for products from many manufacturers) does not work. At a quick glance of your code calling FB41, I can notice that your parameters Com_Rst, and Cycle (for starters) are not initiated. I can tell you that without these the closed loop cannot be initiated, or operate correctly. The initialization routine of the FB 41 is active with the value of Com_Rst, so it is recommended to set it to 1 in OB 100, ans reset it to 0 in OB 35 (or even OB 1) so the FB 41 starts up properly. The Cycle parameter provides the S7 controller the time limits for the closed-loop calculations, these must be the same as the cycle value of OB35. The loop will start in Manual mode, you must force it to Auto mode if you want it to ptocess your dayta and calculations. Yep, that would be the Man_On parameter. Here are a few documents that could help you out: - A FAQ on FB 41/SFB 41 parameters: - A discussion on FB 41; you can search the forum for more posts from hdhosseini, Hamid has answered many questions on control loop design on the forum over the years - A tutorial document from Siemens on SFB 41, it has a very good example of how to launch ithe Control-loop Parametrization software from Step 7 (this application sets the basic startup parameters without your intervention). Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 4/22/2017 12:13:57 PM |
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