4/3/2012 3:44 PM | |
Joined: 12/22/2006 Last visit: 1/25/2022 Posts: 1742 Rating: (308) |
Hello, 1) I would try firts the normal way. Creating an S7 connection in Netpro between the 2 PN ports. This conncetion is TCP/IP based, and will trigger repetitions on lost packets. Test the setup first with a direct connection between CPUs, that you are sure that it works. Than place the radio connection in between. Here you use the blocks PUT, GET or BSEND-BRCV as usual on S7 connections. 2) you could also use UDP (is a non aknwoledged protocol). The loss of a frame will not be detected. Your application must now take care of this. Here the connection is not configured via Netpro, but described in a databloc. There is a wizard available to create the connection description. Here you need other blocs (TCON, TUSEND, ...). Procedure is described in 2 links: http://support.automation.siemens.com/WW/view/en/31930487 http://support.automation.siemens.com/WW/view/en/47885893 |
Best regards |
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4/6/2012 3:44 PM | |
Posts: 23 Rating: (0) |
Hi, UDP connection is great idea, that has never crossed my mind. (TCP need Full-duplex connection and i have only half-duplex) May I have a few question to example in: http://support.automation.siemens.com/WW/view/en/31930487 1) input parameter LOC_PORT of FC96 is L#2001 This is from HW_config PN-IO address Local station? 2) input parameter REM_PORT of FC95 is L#2000 This is from HW_config PN-IO address Remote station? 3) Even if one side is only sending data and the second only listening, in both CPU I have to call FC96 SET_UDP_ENDPOINT and FB65 TCON. Sending CPU is using FC95 SET_UDP_REMOTE and FB67 TUSEND Listening CPU is using FB68 TURCV. I´m right or not? Thans for your advice and reply. |
Last edited by: PilotPM at: 4/6/2012 3:47 PM |
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4/7/2012 10:46 AM | |
Joined: 12/22/2006 Last visit: 1/25/2022 Posts: 1742 Rating: (308) |
Hello PilotM, May be just a calarification around Ethernet and TCP. It is not true that TCP requires full-duplex. Half Duplex only means that you cannot send and receive at the same time, but you can send in both directions (just only not exactly at the same moment). You must wait that the (radio) medium is free before you may send something. Ethernet is named from Ether and Net, meaning sending over the air. Ethernet arose from AlohaNet that wasradio based and half duplex by nature. The CSMA/CD mechnanism used with Ethernet takes its origin from these radio networks and is intended toregulate the access to a shared medium (half duplex) and eventual collisions that might occure. Theearly versions of Ethernet were coax based and also half duplex. WiFi (Wireless Ethernet) is also half duplex. And you could use TCP/IP over these mediums. Back to TCP and UDP. Both use so called "PORTS" which are 16 bit numbersthat are used to identify a data stream.Its a kind of layer 4 address (where the IP address is a layer 3 address, and the MAC address alayer 2 address). When you send data there is a source port and a destination port. These ports have no relation at all withIO addresses in HWConfig. A lot of ports have a predefined/reserved purpose for well known applications. (example: a web server typically listens on TCP port 80 to incoming connections, a PLC waits on TCP port 102 for incoming S7 connections). To avoid conflicts, when you set up an own application, takehigher port numbers.Simatic starts mostlyfrom 2000 upwards.There is a link that lists some of the most used ports (http://support.automation.siemens.com/WW/view/en/8970169). To your point 3) regarding UDP Yes you need TCON on both sides (alsos at the listening side, to "open" the PORT that receives the data stream). TUSEND to send dataat the sender TURCV to recive data at the receiver |
Last edited by: jklm at: 4/7/2012 10:49 AMBest regards |
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4/11/2012 3:38 PM | |
Posts: 23 Rating: (0) |
Thanks for help. UDP was right way. |
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