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About selim

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  1. Yes Saragani, you were right! I was building correct packets but couldn't deliver them correctly to the PLC. And I figured out this just after "sniffing" the packets.. Let me explain why I can't send packets from Delphi to PLC: Indy components are using blocking mechanism. Which means you write and read from a socket "synchronously". This simply just like a console application I/O. I was using; IOHandler.WriteLN() method for sending my packet which accepts STRING as parameter. Therefore I was building my PCOM packet on a local Pascal string. And if you set a character value as zero it means your string is terminated. Although I was building correct packets, remote device had only seen first three characters because fourth character was always zero on the ethernet header.. To solve this problem, I did following: MsgBufferDump: array[0..19] of byte = ( $AA, $08, // Transaction id = 2218 101, 0, // Protocol ID : 101 = ASCII 14, 0, // Payload size = 14 47, // STX: '/' 48, 48, // unit id = 00 82, 87, // Command: 'RW' (Read MIs) 0, 0, 0, 0, // Vector base: will be filled by calling method 53, 53, // Vector length is fixed: 85 ($55) 0, 0, // checksum : will be calculated just before sending 13 // ETX: <CR> ); Before sending, I copy this array to a stream: sendstream:= TMemoryStream.Create; sendstream.Write(MsgBufferDump,20); sendstream.Position:= 0; // if you dont do this you will get an exception IOHandler.Write(sendstream,20); sendstream.Free; And now it is running properly. Thank you very much for your interest.
  2. Hi there; I need to access MI area of a V1040 PLC through ethernet. I had written a code that communicate with PLC via serial port before for an another project. Now, I am planning to modify my code to run under TCP. At PC side, I am working with Delphi XE2 using Indy TCP client component. I tested these components on my network with another computers and they work properly. At PLC side, I am using socket 1, port #20256 and Protocol is TCP Slave.. (I think these are default settings of socket 1 so I don't need to add a socket init FB to my ladder, am i right?) PLC info mode says that card is initialized and socket is connected. In addition, when I send a PCOM string, RX counter increases which showed on info mode but the most important thing is missing: There are no replies. The string I sent is a valid PCOM message which returns answer while I sent it over serial port and plus 6 bytes of ethernet header at the leading. Can you please help me to figure out where is my mistake? With my best regards
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