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400h with 443-1

Created by: Webpower at: 4/27/2008 7:05 PM (7 Replies)

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4/27/2008 7:05 PM	Rate (0)
Webpower Experienced Member Joined: 2/15/2008 Last visit: 7/18/2024 Posts: 32 Rating: (1)	I have 3 plc 400h (1 rack, 2 cpu 414h, 1 symlink, 2 cp443-1). The plc are connected via optical fiber. Each cp4431 is connected to an olm. At the end of the fiber i've a pc, with a software that user s5_protocol or fetch/write to read the data from the 3 plc. Every plc must communicate with the other plc. PLC1 PLC2 PLC3 PC olm 1------------------ olm 1-------------------------olm 1--------------------- olm 2-------------------olm 2--------------------------olm 2---------------------- The questions are : 1) if in plc1 run on cpu A, plc 2 on plc B, and plc3 run on plc A the communication is still ok ? 2) if olm2 breaks on plc2 and plc2 is running on cpu b the communication is still ok ? 3) must i insert a hub in every place and mix the different subnet ? thx

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4/28/2008 2:42 PM	Rate (0)
J_Bell Posts: 5822 Rating: (412)	Dear Webpower, well... there are two things to take care of. First of all, the H Systems should not communicate on Fetch/Write between each other, because there the PLC will not notice if the Communication breaks... and you have to manage too much. So what I would do is the following: Use S7-H Connections between the PLC’s. That way you can be sure that the Connection is handled by the System itself and is always available. You can even check the State of the Connection from within the PLC Program. So that is much easier. That way you can use either PUT/GET of BSEND/BRECV, depending what you need. Form the PC side it is even worse. The use of Fetch Write from a PC to an H System would require a lot of management, why do you not use S7-Redconnect with two CP 1613 in this case? Best regards J_Bell
J_Bell Posts: 5822 Rating: (412)
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4/28/2008 6:42 PM	Rate (0)
Late Platinum Expert Joined: 1/7/2006 Last visit: 11/17/2023 Posts: 2705 Rating: (319)	Hi, I agree with J_Bell, redundant communication between the H-Systems is easier then doing some other communication, this because the system is taking care of the redundant communication. To an PC I will also advice to use RedConnect as J_Bell mentioned, all other redundant communication that you set up without RedConnect will be a disaster. It is not that difficult to communicate redundant when there is no trouble, but when trouble starts then it is not that easy. I have seen a lot of people that are saying ohh... I made that by myself... they are still working on that project...
	I hope that the answer will help, if you have still questions, don't hesitate to ask me. All the best, Late Never say never, think in solutions, not in trouble......
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4/28/2008 11:30 PM	Rate (0)
Krish Silver Member Joined: 5/24/2007 Last visit: 4/24/2024 Posts: 284 Rating: (27)	Dear Webpower I fully agree with Late and J_Bell. You will save a lot of trouble using redconnect with CP1613 cards installed. But just in case you have communication between plcs ( eg PLC 1 and PLC 2), thenit is better you use a scalancesystem instead of OLM to maintain communications between PLCs even if one of the CPUs or CPs in the communication PLCs fail.

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4/29/2008 3:20 PM	Rate (0)
Webpower Experienced Member Joined: 2/15/2008 Last visit: 7/18/2024 Posts: 32 Rating: (1)	Thx for the suggestion. In real the net is made with a optical ring and scalance hubs. I will try to manage the communication from Pc to Plc by myself, detecting the ethernet channel working (using the information collected form the diagnosis by the plc). If i'n not able or the communication is too complex i will use redconnect and cp 161-3 Bye

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4/29/2008 6:30 PM	Rate (0)
Krish Silver Member Joined: 5/24/2007 Last visit: 4/24/2024 Posts: 284 Rating: (27)	Well Webpower I guess after all this strong advise if youare still wanting to establich connection using your own PC software I guess you have budget/deliverycommitments. I was in thesame situation a while ago. So just that you don´t burn your fingers like I did,consider the following. TheTCP/IP connection youestablish is betweenCP443 and the PC and not theCPU. This means that though the CPU would have gone into stop the CP connection will not be dropped (it should not as otherwise how would read the diagnostics of the CPU or the program through a programming terminal). So this means that you have to somehow find a way to disconnectfrom the running CP to the standby CP when the CPU fails. One way is to establish a watchdog and when you don´t get the watchdog from the CP you switch over(I implemented this). But if process does not support it , then you have to do it in a very tricky way. If you are cyclically only reading data , let the PLC establish connection everytime and after transfer disconnect it after the job is done. The PCalso expects connection top be alive for only the short periodand so after time out(in case CPU failed in between) you can disconnect from the PC side. If your PC application is tight and not so easily configurable,I have heard ofsomebody doing using an SFC55 to write the ip address of the particular CP you are using. But Idid not attempt it. Letus know how you approached once your finished. It could enlightenus all.

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4/30/2008 9:13 AM	Rate (0)
Webpower Experienced Member Joined: 2/15/2008 Last visit: 7/18/2024 Posts: 32 Rating: (1)	In my application i don't use opc or other software to communicate with the cp. I write personally the driver of communication, and i use a programmin languaage to develop (delphi or c++). The code is very flexyble, i think to communicate with both the cp on the redundant plc, detecting with watchdog and some other thing what is the channel really working. At this stage i try this solution, if is not safe or too complicate i will switch to the redconnect solution. In future the supervisor must be installed on two or three pc, and the cost of the redconnect + 161-3 is considerable.... Bye

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1/1/2014 10:28 PM	Rate (0)
CS Moderator Moderator Joined: 9/1/2005 Last visit: 12/12/2024 Posts: 4114 Rating: (195)	follow up question published byopheris split to a seperate thread with the subject Communication via Profinet port on CPU 412-5H - use the driver of LIBNODAVE Best regards CS Moderator
	My Forum is the place to personalize your profile, track your topics, and maintain content that interests you. Best regards CS Moderator
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