5/6/2012 4:02 PM | |
Posts: 94 Rating:
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Ya Smiffy please do the needful... Regards. |
5/6/2012 8:08 PM | |
Posts: 2 Rating:
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Thank u SMIFFY thats nice from u, that will help us more, and i hope that we don't bother u |
5/7/2012 1:11 PM | |
Posts: 22 Rating:
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Dear Arun, this will surely help you.. http://www.plcmanual.com/isoosi-model Enjoy.. |
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7/20/2012 4:00 AM | |
Posts: 29 Rating:
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its a good read. thank you for that effort. Yvon
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9/29/2012 12:42 PM | |
Joined: 9/27/2006 Last visit: 8/16/2024 Posts: 12277 Rating:
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Hello hunky; It is indifferent which of the 2 (CP 441-2 or DCS) is master on the bus, especially if you have only these 2 nodes on Modbus RTU. Choose one to be master based on ease of programming and familiarity, If you select the DCS as master, you will have to program the Modbus jobs in the DCS, and choose: - Write multiple coils (Modbus function 15- write to the 0000x outputs of the PLC) -Write multiple registers (Modbus function16- write multiple 4000x registers to the PLC) -Read input registers (Modbus function 04- request 3000x registers from the PLC) -Read discrete insputs (Modbus function 02- request 1000xinputs from the PLC) Of course if the roles are reversed you would have to select the Modbus jobs in the Cp 441-2 so you would write digital and analog inputs to the DCS, and read digital and analog outputs to the PLC. The slave will only reply to the master when Modbus jobs are sent to it, so everything is to be planned from the master's point of view. I do not know how difficult it is to use Modbus RTU on your DCS, but it might be easier to let the CP 441-2 act as a slave, therewould very little programming to be done on that side. Have a look at the following sample program for Modbus slave functions proposed by member Amit recently: /tf/WW/en/Posts/72742 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 9/30/2012 5:22 PM |
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10/3/2012 12:16 PM | |
Joined: 11/8/2011 Last visit: 7/2/2024 Posts: 387 Rating:
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Thank you its very useful,I hope that you can explain to us more about profibus and ethernet protocols |
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