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S7-400H ethernet issues

Created by: ste_angioni at: 9/29/2010 9:11 AM (1 Replies)

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9/29/2010 9:11 AM	Rate (0)
ste_angioni Bronze Member Joined: 1/3/2009 Last visit: 6/30/2022 Posts: 161 Rating: (12)	Hi all, I am going to design a control system based on S7-400H CPU (probably 412-3H) and, as per customer specification, the PLC must act as a modbus TCP/IP server for their DCS. The control cabinet will be equipped with an operator interface (it will be a MP-377). So I have a few questions about ethernet: 1.Using a CP 443-1, is it possible to be a modbus TCP/IP server? 2.Which is the IP addresses behaviour in case of CPU switchover? Does the master CPU keep the same address, or are the IP addresses related to the rack where the CP are installed? 3. Is it possible to have HMI communication over the same network we are using for modbus TCP/IP Any help will be very appreciated. Stefano
	Stefano Angioni Automation Dept. REMOSA S.p.A. http://www.remosa-valves.com
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9/29/2010 3:31 PM	Rate (0)
dchartier Grandmaster Joined: 9/27/2006 Last visit: 11/7/2024 Posts: 12293 Rating: (2691)	Hello Stefano; In the following link, you will find information and manuals for Open Modbus/TCP, a development from the IT4Industry division of Siemensthat allows a CP 443-1 to act as a Modbus/TCP server or client. There is even a special design for a redundant application of Modbus/TCP, which would simplify your situation. Of course you could design your own application (multiple connections, lifebeat monitoring, connection switching conditions...) for redundancyif you prefer. Modbus/TCP is based on TCP/IP and so can share the bandwith of your Ethernet network with other TCP/IP comms without too many problems, as long as you use adequate hardware (especially good quality switches) and that you make sure the exchanges do not overwhelm the network (no brodacast or multicast). So you could connect the HMI to the PLC with either TCP/IP or ISO-over-TCP connections using the same CPs. In this link you will see multiple threads that have been posted on the forum requesting help on various projects using Open Modbus/TCP. Maybe some of the information will help you: https://support.automation.siemens.com/WW/llisapi.dll?query=open+Modbus%2FTCP&func=cslib.cssearch&content=adsearch%2Fadsearch.aspx%3Ftab%3D2&lang=en&siteid=csius&objaction=cssearch&searchinprim=_searchinprim_&nodeid=99&x=16&y=8&cssearchengine=NEW Hope this helps, Daniel Chartier

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