1/2/2021 8:18 PM | |
Joined: 12/18/2014 Last visit: 8/17/2024 Posts: 33576 Rating:
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Please use search function of the forum. There are so many examples for pump control. |
1/3/2021 11:29 AM | |
Joined: 4/9/2009 Last visit: 6/25/2024 Posts: 66 Rating:
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Hi ixo65 thanks for the clarification, probably my first post wasn't clear. In attachment you can see the program already developed and tested. Some notes: - I1 = Fault P1 - I2 = Fault P1 - I3 = Common fault - I4 = Level 1 - I5 = Level 2 - Q1 = Start P1 - Q2 = Start P1 The level 1 and level 2 can be activated in any sequence, In my opinion the logic developed should already work for alternation, switchover in case of fault, activation of all pumps available in case of both command level, etc. I would like to solve theese two problem: PROBLEM 1 (Shutdown sequence) First pumping cycle Level 1 = On --> P1 On (ok) Level 2 = On --> P2 On (ok) Level 1 = Off --> P2 Off (not ok - pump 1 should turn off) Second pumping cycle Level 1 = On --> P2 On (ok) Level 2 = On --> P1 On (ok) Level 2 = Off --> P2 Off (not ok - pump 1 should turn off) PROBLEM 2 It seems that when switching from two active levels (both pumps on) to only one active level, for one program cycle both pumps are switched off... The same logic implemented in S7-1200 doesnt have this stange behavior. Thanks and Best Regards AttachmentAlternationTest.zip (282 Downloads) |
1/3/2021 5:08 PM | |
Joined: 4/9/2009 Last visit: 6/25/2024 Posts: 66 Rating:
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Hi ixo65, first of all thanks for reply and dont worry for possible misunderstandings Yes, I know that the programming of an S7-1200 PLC is different from a LOGO! but, in principle, if you use LADDER programming with only parallel and serial logic gates it is quite simple then transform the logic from S7-1200 to LOGO!. However, if you are interested, the TIA Portal project is also attached. The big problem, however, I think it is number 1 mentioned in my last post because, for number 2, I think that in the real PLC it shouldn't even have time to really shut down the pump Thansk and Best Regards Roberto AttachmentTestLogo.zip (245 Downloads) |
1/4/2021 4:06 AM | |
Joined: 12/18/2014 Last visit: 8/17/2024 Posts: 33576 Rating:
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In my opinion, the problem is the marker M3, which has a HIGH signal when both levels have a HIGH signal and then switches off one level. Both pumps are then switched off in the same cycle. The priority pump can only be switched on again in the next cycle, since the output of the non-priority pump must report a LOW signal. A typical cycle problem. See attached video...
AttachmentCycle problem.zip (267 Downloads) |
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