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MODBUS MASTER

Created by: NimaMoaddeli at: 5/26/2009 9:37 AM (6 Replies)

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5/26/2009 9:37 AM	Rate (0)
NimaMoaddeli Posts: 32 Rating: (0)	[schnipp-schnapp] Can you also help me on MODBUS MASTER, I have some experience with modbus communication in STEP 7 with CP341 as MODBUS RTU master and slave, but Here I'm going to communicate with alen bradley PLC. I will be as master for that, but the mater is that in STEP7 I have access to Data Block and anything but here How can I do it? Is there any refernce for this? Best Regards
NimaMoaddeli Posts: 32 Rating: (0)	Last edited by: O_Moderator at: 5/26/2009 2:38 PM new subject after splitting
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5/26/2009 10:04 AM	Rate (0)
Sydney Gold Member Joined: 1/4/2008 Last visit: 9/26/2024 Posts: 703 Rating: (96)	Sorry, I don't have experience with the Modbus comm to Allen Bradley PLCs. But there are alreadysome threads about it in the forum, try to search for Modbus and if you don't find what you need then create a new thread in theCommunication conference. Regards Sydney

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5/26/2009 6:27 PM	Rate (0)
daga Gold Member Joined: 3/18/2009 Last visit: 12/6/2024 Posts: 306 Rating: (94)	NimaMoaddeli I will be as master for that, but the mater is that in STEP7 I have access to Data Block and anything but here How can I do it? In PCS7, for using CP 341 as modbus master you can use FB 120 (SND_341) and FB 121 (RCV_341) from the pcs7 library. The online help gives you necessary information. To use the above blocks you need to understand how to handleAny pointer in CFC. To access Data Block in CFC, you can go throughthis FAQ Another easier solution is to use the modbus communication library S7HMODM3. Thelinkto it's manual. www.industry.siemens.com/industrial-services/en/downloads/MODBUS_D.pdf The last page has contact details from where to get it.(Sorry, it is in german - I do not know the link to it's english version. And it is too big to upload it here) A third solution, though very crude, could be that you write everything in an FC in Step 7 (and just call the FC in a CFC chart.Though remember to use appropriate FC and DB numbers from the "Areas Reserved for Other application" (In CFC editor, Options>Customize>Compile/Download...) This method may require an entire download.

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5/28/2009 12:08 PM	Rate (1)
Wüstenräuber Gold Member Joined: 10/3/2008 Last visit: 12/12/2024 Posts: 966 Rating: (127)	Hi, you can use "OpenModbusTCP CP" as well. In this forum there is an extraconference: OpenModbusTCPwith many interesting threads. Wüstenräuber

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6/3/2009 3:25 PM	Rate (0)
CBo Gold Member Joined: 4/5/2006 Last visit: 12/12/2024 Posts: 917 Rating: (63)	Hi NimaMoadelli, there is onether tread where you can find manual daga said obve, in english version. One more, there is no problem to link DB into CFC block, just have to remebr you don't have to use structure/array into DB's. Reagards

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6/22/2009 10:24 AM	Rate (0)
how come Posts: 382 Rating: (47)	Dear NimaMoaddeli, Since you are mentioning that you are communicating with allen bradley PLC, do remember that if you are using allen bradleymodbus card, there are dip switches setting in the card in order to establish the communication. Hope this helps! with regards, how come?
how come Posts: 382 Rating: (47)
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6/22/2009 10:59 AM	Rate (0)
Gunners Posts: 130 Rating: (18)	Hi, This is once discussed in one of the threads. I guess this can help you. /tf/WW/en/Posts/11015 regards,
Gunners Posts: 130 Rating: (18)
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