6/28/2010 12:30 PM | |
Posts: 48 Rating: (0) |
Hi, I tried to collect data from a siemens 300 plc over ethernet through OPC.Simaticnet with a VB.Net program and write it into a flatfile as raw data. I wrote it with the help of sample programs with Simatic net 2008. I got data ok. But I can't understand it fully. I analysed the flat file using a Hex Editor. First I read only one Item. Real variable - DB2.DBD0 - I got 6 bytes instead of expected 4 bytes. ( 2 bytes extra.) Then I read two in combo (Quantity =2) Real variable - DB2.DBD0,.DB2.DBD4 - I got 20 bytes instead of expected 8 bytes.( 12 bytes extra.) As i went on with 3 ,4..., All come with the 12 bytes extra. So i believe the 12 bytes is some header string. This is what i got for 15 consecutive real variables. [04 20 01 00 0F 00 00 00 00 00 00 00] Then my data. Can Any body explain the structure of this 12 bytes. ( All in Hex format) Regards, Nithin AttachmentVB_net script - Notepad.pdf (96 Downloads) |
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