11/2/2014 4:25 PM | |
Posts: 6 Rating: (0) |
Hi, I'm working on my final year project. I am interested in programming the plc through PC, which inturn will command VFD drive through serial communication port as uploaded in the picuture below. Problem is, my plc s7 200 CPU 224 provides with only one rs 485 port. How do I use builtin rs 485 plc port to communicate with PC and VFD aswell? Can I make some arrangment likethisand solder three db9 ports? I am very new in automation and any kind of help will be appreciated. |
11/2/2014 9:03 PM | |
Posts: 5225 Rating: (1184) |
Hi buddy, Did you know that "RS485" is a description of the hardware? You will have to also include the protocol ("language") that is going to be used on the hardware line. Which VFD / VSD / inverter do you plan on using? I expect you will have x2 choices on the protocol.. Modbus RTU or USS Protocol. Yes.. other protocols are available, but these are the most logical choice. The trouble with either of these before mentioned two - the libraries available for the S7-200 is not for free. You have to order it - unless you already have it available. Remember also that the S7-200 is now declared obsolute, so this may be a bit of a challange to get through normal channels. If you would use the S7-1200 PLC, you would have the protocol available as a standard library.. but you will need an add-on hardware component. Having only x1 port is only a problem when you need to communicate to the VFD and the PC / HMI at the same time. Otherwise you can use the RUN / TERM / STOP switch on the PLC to select between protocols. On TERM you could have the PLC "talk" in PPI and when set to RUN the PLC can "talk" in USS Protocol - for example. Please come back with some of your thoughts if this discussion needs to continue. Good luck! w |
Last edited by: William B. at: 11/2/2014 9:25 PMalso see.. /tf/WW/en/Posts/116903#589375 |
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11/2/2014 9:24 PM | |
Posts: 5225 Rating: (1184) |
Hi there, This is a good place to ask this question. Your questions are now all over this forum, which will make it difficult for us to focus our energy.. the risk is in us repeating each others' answers. Please review answers.. [LINK] [LINK] Then I recommend you choose which of your multiple posts you are going to stick to, to receive answers from our community. Regards. |
12/17/2014 10:26 AM | |
Joined: 5/1/2009 Last visit: 5/23/2021 Posts: 144 Rating: (1) |
Dear Musaib Are you accomplished your project ? if yes- i hope - can you help me about how can read and write from VFD Delta where the address as following 2001H 2002H 2102H how can write this address on modbus block ? thanks for your support |
Best regard |
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7/18/2019 7:59 AM | |
Posts: 1 Rating: (0) |
Dear Musaib did you solve this trouble ? if you solve this how did you solve. is serial communication possible to communicate plc and labview |
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