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Created by: kristine at: 5/6/2009 3:14 PM (34 Replies)

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5/6/2009 3:14 PM	Rate (0)
kristine Posts: 17 Rating: (0)	Hello Everybody, I am a last year student at University College Oslo, Norway. I am having my project where i have to establish ModBus communication between two simulators made in Labview and a PLC (315 2PN/DP). I bought modbus library from it4business, I did everything i could according to manual followed by Modbus Library. I think i have little bit problem in parameterisation of the DBs because i got sucsessfull in establishing connection between PLC and the PC with Labview simulator but problem is that i cannot receive data from simulator. Can anybody help me plz having any example of such a program send me at kristinep80@gmail.com ,example followed by Modbus library didnt worked for me, or can anybody help me if i send my copy of program just email me.its urgent Thanks and Regards Kristine Pettersen
kristine Posts: 17 Rating: (0)
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5/6/2009 4:57 PM	Rate (0)
safety4ever Experienced Member Joined: 12/5/2006 Last visit: 2/6/2024 Posts: 73 Rating: (4)	Hi you did not clarify whether you are using Modbus TCP or RTU if sois the S7 CPU modbus master or slave? If you are using Modbus TCP on the integrated port with the CPU there are some examples under this link http://support.automation.siemens.com/WW/view/en/22660304 Other wise if you are using RTU (CP 341/340) once you install the SW you would have examples projects once the installation is completed. If you are communicating with multiple partners on RTU I recommend the RS485/RS422 serial module.

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5/6/2009 7:47 PM	Rate (0)
kristine Posts: 17 Rating: (0)	Thank You, I am using Modbus TCP.The PLC is a slave/client Do you have any examples? I did everything i could according to manual followed by Modbus Library. I think I have little bit problem in parameterisation of the DBs because i got sucsessfull in establishing connection between PLC and the PC with Labview simulator but problem is that i cannot receive data from simulator. Could you please take a look on my program? It would be very kind of you. Thanks and Regards Kristine Pettersen
kristine Posts: 17 Rating: (0)
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5/6/2009 10:21 PM	Rate (0)
safety4ever Experienced Member Joined: 12/5/2006 Last visit: 2/6/2024 Posts: 73 Rating: (4)	Normally the Wizard for Modbus TCP should be taking care of the DB's parametrization just in case you do not have it, it is available here http://support.automation.siemens.com/WW/view/en/31535566. Unfortunately I do not have examples other than the manual is refering to. I have used mostly RTU.

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5/7/2009 12:09 AM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi kristine, in the example project of ModbusTCP there is an example for "S7 as Server" and "S7 as Client". Why it's not good for you? Which addresses do you have parameterized in the parameter DB? And which errorcode occurs on parameter STATUS_MODBUS after you started an order/telegram? With this errorcode you can find the reason for your problem normally. Wüstenräuber

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5/7/2009 9:11 AM	Rate (0)
YngSoul Posts: 15 Rating: (1)	Hi Christine, If you can get the connection established, it should normally be no problem receiving/sending data from/to you communication partner. You should pay attention if the start address + length are also supported by the remote partner and that it's also available in one of the Data areas you parameterized in the Modbus_Param DB. You should check in which DB your Start address+length is available, the data received will be stored there. Good luck!
YngSoul Posts: 15 Rating: (1)
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5/8/2009 12:04 PM	Rate (0)
kristine Posts: 17 Rating: (0)	hi Wüstenräuber, I tried to open that example but I could'nt. It shows nothing when i open S7.server or client. may be because of different hardware configuration but i am not sure,Its first time i am working with Modbus. If you can help me with that ,i shall be very great full to you. If you want so i can send you a copy of my S7 program and Labview simulator. Thanks and regards Kristine Pettersen
kristine Posts: 17 Rating: (0)
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5/8/2009 3:15 PM	Rate (0)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi kristine, it seems that you don't have installed the current hsp-package. You can download from product support sites here. I changed the current example project and attach here. In DB2 the second connection is the connection for a 315 CPU as server. Perhaps you have to change the parameters depend on your firmware version. If your project is not too big, you can attach here (the size is limited in the forum). Wüstenräuber Attachment Modbus.zip (921 Downloads)

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5/11/2009 10:48 AM	Rate (0)
kristine Posts: 17 Rating: (0)	hi Wüstenräuber I saw at your example and my project but it is not to much difference in both. if you can give me your email address so i can send you my Labview and S7 program. Thank and Regards Kristine
kristine Posts: 17 Rating: (0)
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5/12/2009 10:08 AM	Rate (1)
Wüstenräuber Gold Expert Joined: 10/3/2008 Last visit: 8/28/2024 Posts: 961 Rating: (124)	Hi Kristine, I have got your project by the moderator and will check it. Wüstenräuber

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This contribution was helpful to 2 thankful Users S_Moderator kristine

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