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several CP340s in ET200M

9/17/2011 10:11 AM	Rate (0)
wreng Advanced Member Joined: 7/27/2008 Last visit: 11/8/2023 Posts: 25 Rating: (0)	Hello My project isas below CPU416-2DP 26 CP340s (RS422 PtP 9600 ASCII full duplex) is located in ET200M, Each CP340 communcate withRFID controller one by one. I use one P_SEND(FB3)/P_RCV(FB2) function block, but respective instance data block. Send data is only 8bytes and Receive Datais maximum 15bytes. When I trigger send REQof 26 P_SEND function blocks usingone bit simultaneously, but the send function of each CP was processed with time interval. Ittakes totally almost 1sec. Iwant for the send/receive function of each CP to be processed every 0.1sec respectively. Why the send/receive function block is processed time intervally? Because of decetral via profibus-dp? Thanks

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9/17/2011 3:11 PM	Rate (0)
fritz Diamond Expert Joined: 10/7/2005 Last visit: 3/18/2025 Posts: 3042 Rating: (1061)	Hello wreng assuming you operate your Profibus at a half decent speed (let's say 500Kbsor1.5Mbs) it's update time will have an insignificant effect on your serial comms. The problem will most likely lie in the fact that P_SEND and P_RCV use SFB52/53 internally. Please check this by right clicking on them, open the Object Properties and go to the "Calls" tab (I don't have them in my current Step7 install and can't verify this). If SFB52/53 or SFC58/59 are listed as being called from them, you will only be able to have a certain number of simultaneously active callswhich would explain the "long" execution time of all 26 comms job. How many simultaneously active calls are supported is CPU dependant and explained in the FAQ below: What restrictions are there for active jobs when communicating with SFC 58 / SFC 59 and SFB 52 / SFB 53 via PROFIBUS DP and PROFINET IO? I hope this helps and please let us know what you find.
	Cheers fritz The advice and opinion given in this thread is that of the author and does not necessarily reflect the views of I S Systems Pty Limited. To find out how I S Systems can help you with your automation needs please visit www.issystems.com.au.
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9/18/2011 10:36 AM	Rate (0)
wreng Advanced Member Joined: 7/27/2008 Last visit: 11/8/2023 Posts: 25 Rating: (0)	Hello Mr. Fritz Thank you for your quick help I will try again and reply soon. But it may take some weeks due to site condition. regards

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