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Danfoss VFD and PLC

Created by: PILearner at: 6/27/2014 12:35 PM (3 Replies)

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6/27/2014 12:35 PM	Rate (0)
PILearner Posts: 80 Rating: (1)	How do you control a Danfoss VFD using Siemens S7 200 through Profibus. I need complete control of VFD through Profibus?
PILearner Posts: 80 Rating: (1)
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6/27/2014 1:03 PM	Rate (0)
William_B Posts: 5225 Rating: (1195)	PILearner How do you control a Danfoss VFD using Siemens S7 200 through Profibus. I need complete control of VFD through Profibus? Hi. I have not used the S7-200 in a Profibus network, but I have used a Danfoss drives in a Profibus network with an S7-300 PLC. It will help if you tell us if you have worked with Profbus devices before. To get you started, I recommend you visit the Danfoss website and look for exaples and descriptions. Get the full "Design Manual" for your drive. This manual is a must for advanced design. In the manual a descrition is given also of how "serial" communication is handled. An example is given in the PDF so that you know what to look for. Get you head arround how the "telegram" system works. There are also two parts.. on part your PLC will see as inputs and other as outputs. There are several telegram styles to choose from. Each style contain different information. I would not recommend you try and access ALL information from the drive via the PLC.. your communication speed, CPU speed and memory resources will suffer for it. Share again your thoughts on this subject and I am sure someone will help you. Greetings. w Attachment Extract_Danfoss VLT design manual.pdf (710 Downloads)
William_B Posts: 5225 Rating: (1195)
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6/27/2014 1:25 PM	Rate (0)
dchartier Grandmaster Joined: 9/27/2006 Last visit: 11/11/2024 Posts: 12293 Rating: (2691)	Hello Learner` Just one basic point: the S7-200 cannot act as a Profibus-DP master, you can only set it up as a Profibus-DP slave using an EM 277. Only a Profibus master can read/write to a Profibus slave, so the configuration you are asking for is not possible. When controlling a Siemens drive, the S7-200 uses a protocol called USS. very close to Profibus-DP but with limitations. William"s comments would still be important if you use USS with your Danfoss drive. I remember hearing that some models from Danfoss supported USS, I suggest you talk to your Danfoss rep and see what you can do with your system. Danfoss also supports Modbus RTU on some models, which can be implemented on a S7-200 (with the purchase of a USS/Modbus library for MicroWin). Look at the S7-200 system manual to see what functions cn be implemented with USS or Modbus. S7-200 System Manual Come back to the forum when you have more answers for your drive comms. Hope this helps, Daniel Chartier
	Last edited by: dchartier at: 6/27/2014 1:30 PM
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This contribution was helpful to 1 thankful Users William_B

6/27/2014 2:09 PM	Rate (0)
William_B Posts: 5225 Rating: (1195)	dchartier Just one basic point: the S7-200 cannot act as a Profibus-DP master, you can only set it up as a Profibus-DP slave using an EM 277. Only a Profibus master can read/write to a Profibus slave, so the configuration you are asking for is not possible. Daniel, Thanks for catching that one! I have totally forgotten about it. In actual fact I would rather consider using an S7-1200 for the job. This can handle Profibus as master. [LINK] The question comes in.. Is a Profinet network with S7-1200 not something to look at as alternative? w
William_B Posts: 5225 Rating: (1195)
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