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wrong input state at program startup of LOGO! 8.3

Created by: pmlaforest at: 4/12/2021 10:47 PM (11 Replies)

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4/12/2021 10:47 PM	Rate (0)
pmlaforest Posts: 4 Rating: (1)	Hello everyone, I have a LOGO! 8.3 (6ED-1052-2MD08-0BA1) connected to two expansion modules (6ED1055-1MB00-0BA2). Both CPU module and expansion modules are powered by a 24V supply. So far so good. So far so good but here is the deal : I4 of the first expansion module's input (I12 total) is also connected directly to the 24V supply. At program startup, during one or multiples of the first scans, the input in question is read as 0V. I know that the first scans are causing the problem because when I add an ON delay timer of 500 ms at program startup before evaluating the input, the rung works as expected and the problem does not manifest itself. When the problem occurs, flag M38 is "latched" and the only way that this can happen is when I12 is at 0V, which is surprising because I12 is wired to the 24V supply. See attached picture for more details. We first noticed this problem when we changed the model of our LOGO! (8.2 6ED-1052-2MD08-0BA0 to 8.3 6ED-1052-2MD08-0BA1). Does someone have a clue on what can be causing the problem here ? PM Laforest Attachment input glitch at startup.png (806 Downloads)
pmlaforest Posts: 4 Rating: (1)
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4/13/2021 2:13 AM	Rate (0)
ixo65 Grandmaster-Expert Joined: 12/18/2014 Last visit: 12/22/2024 Posts: 34442 Rating: (4294)	Hmm, strange behavior. Since I do not have the same hardware (no 6ED1055-1MB00-0BA2 expansion module) and neither do I have your program, so it's difficult to make a statement. If Siemens doesn't provide any absolute information about what exactly was changed when the model changed from LOGO! 8.2 to LOGO! 8.3, no one except Siemens can make a clear statement. I would recommend to start a Support Request.

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4/13/2021 1:40 PM	Rate (0)
pmlaforest Posts: 4 Rating: (1)	Yes, and I have already started a support request. I agree with you, this is a strange behavior. The more I talk to people the more likely it is to be an hardware problem. But which one ? Is it really a bug inside the LOGO!, or is it either the CPU or the expansion module in question that gone bad. We'll see, I'll try to update this as soon as we pinpoint the exact cause of this problem. Pierre-Marc
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4/13/2021 1:55 PM	Rate (1)
Scorp Platinum Member Joined: 2/22/2008 Last visit: 11/18/2024 Posts: 2698 Rating: (208)	Have a look to the setup in the Logo menu, there is a Power-on Delay settable from 1 to 10s. Maybe this will help you. I don't know, which Logo hardware was the first version with this option. Regards, Scorp

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4/13/2021 3:15 PM	Rate (0)
pmlaforest Posts: 4 Rating: (1)	Thank you for your idea Scorp. I haven't found the LOGO menu that you mentionned. In LOGO!Soft Comfort v8.2/8.3, are you talking about the offline settings, the online settings or something else ? But a settable power-on delay of 1 to 10 sec doesn't add up with the fact that a 500 ms on delay timer solves the problem no ? Pierre-Marc
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4/13/2021 3:24 PM	Rate (0)
ixo65 Grandmaster-Expert Joined: 12/18/2014 Last visit: 12/22/2024 Posts: 34442 Rating: (4294)	Go to the LOGO! menu. Then switch the LOGO! in Stop. Then select the menu point "Power-On Delay" and then press enter. Now you can set the delay time between 1s and 10s.

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This contribution was helpful to 1 thankful Users Mohammad Razmjoo

4/13/2021 11:57 PM	Rate (0)
Scorp Platinum Member Joined: 2/22/2008 Last visit: 11/18/2024 Posts: 2698 Rating: (208)	pmlaforest Thank you for your idea Scorp. I haven't found the LOGO menu that you mentionned. In LOGO!Soft Comfort v8.2/8.3, are you talking about the offline settings, the online settings or something else ? But a settable power-on delay of 1 to 10 sec doesn't add up with the fact that a 500 ms on delay timer solves the problem no ? Pierre-Marc If i see it right, you have a Logo without display ? Then i don't know, how to change the menu settings, because i can't find this setting in Logosoft comfort. Maybe it would be better, always to use a Logo base module with display or you have a TDE display, which also offer the menu settings. Background of my idea is, that the Power-on delay only delays the program execution of the base module, not the readiness of the expansion modules. If you have no access to the settings, then use timers in the program to avoid problems as you have described. Regards, Scorp

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4/14/2021 7:29 PM	Rate (1)
M111 Bronze Member Joined: 8/2/2018 Last visit: 12/16/2023 Posts: 302 Rating: (5)	May be we can use start up flag M8 to make delay or disable some logic in program on first cycle LOGO starting. Just my idea.

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5/6/2021 9:50 PM	Rate (1)
pmlaforest Posts: 4 Rating: (1)	A couple of guys at siemens reproduced the bug and experienced the same behavior. Namely with a LOGO! 8.3, the expansion module's inputs are at 0V until the exp. module finishes its initialization so if you latch a flag during that time like we did, you could get into trouble. We solved the problem by using a "custom" power-on delay timer. Pierre-Marc Laforest
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7/30/2022 5:40 AM	Rate (0)
Mohammad Razmjoo Experienced Member Joined: 9/14/2021 Last visit: 1/31/2023 Posts: 99 Rating: (0)	Hi there, I think that is the clue on Siemens LOGO Manual (This manual applies to LOGO! 8 6ED1052-xxx08-0BA1device series) : Note After switching the power on, the system briefly switches through the outputs on the LOGO! 24CE/24CEo. With an open circuit, a voltage of > 8 V can occur for up to approximately 100 ms; when the circuit is loaded, this time reduces to a matter of microseconds. Please visit screenshot I attached Attachment first scan.jpg (638 Downloads)
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This contribution was helpful to 1 thankful Users Silli_ML

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