3/30/2010 7:26 PM | |
Joined: 3/25/2008 Last visit: 1/28/2022 Posts: 232 Rating: (20) |
Hello dear experts. We need to know if the Network topoliggy showed in the attached file is correct to acomplish with this requirements: 1. Every IM154-8 showed in the picture shuld be able to work as DP master. 2. Every IM154-8 will be configured to read and send data to all the DP slaves of thecorresponding station. 3. Every IM154-8 should be able to exhange data with the CPU319 Showed. Perhaps somebody can tell us pelase: a. How many repeaters(maximun) can we add into the profibus network of CPU319? b. Should the CPU 319 run as master or slave? c. Can we use DPcouplersinstead dp repeatersto run CPU319 and IM154-8 asDP masters and exchange data between them? Thanks all you for your help, any suggestions will be very helpfull. Have a nice day all you . AttachmentHW_profi.pdf (149 Downloads) |
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3/31/2010 9:55 AM | |
Joined: 10/7/2005 Last visit: 9/22/2024 Posts: 3021 Rating: (1054)
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Hello TEBANCH here's my take on your questions: 1.) You could have up to 31Repeaters directly "hanging" off the DP port of your 319. This ishowever not a repeater limit, but rather an RS485 limit which allows 32 devices per segment (a reapeater counts as a device in this case due to its RS485 interface and even though it does NOT have a Node address. The CPU is the otehr device). If you cascadethe repeaters (i.e.repeater connected to the "repeated" port of another repeater) downstream port), you can have a maximum cascading depth of 9 repeaters (this is a Siemens repeater"limitation"and has to do with timing "inaccuracies' that are introduced when the Signal is repeated). Bottom line: No issues whatsoever with the 4 repeaters that you have foreseen. 2.) It should be a DP Master. If it is a DP Slave it can only bea DP Slave for ONE of the four IM154-8 CPU's which emans the three others will miss out on being able to talk to the 319. You will in this case need DP/DP couplers though to communicate between the CPU's (the onboard DP port of the 319 as well as the IM154-8 CPU's can unfortunately only act as a Server for S7 communications but NOT as a Client, so you can NOT configure S7 connection between the PLC's) 3.) Yes you can and this is possibly the best way forward for you if you really need to link the 319 with all four IM154-8 CPU's via their Profibus DP ports. Note the following "limitations" though in this case: - You can exchange a max number of 244 Bytes (both ways) via eachDP/DP coupler. - The 270 MPPanel won't be able to "see" or directly communicate with the 319 (it can NOT see past the DP/DP coupler). It will be able though to talk to it's "local" IM154-8 CPU. Having said all of the above, I wonder why you don't use Ethernet for the comms between the 319 and all four IM154-8 CPU's (all of your CPU's have an onboard Ethernet port and you can then set up S7 connections between them and use for example GET/PUT or BSEND/BRECV or USEND/URCV comms)? I hope this helps |
Last edited by: fritz at: 3/31/2010 9:57 AMWizard beat me to the answer, I guess I''ll have to learn to type less or faster or both .... Cheers |
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