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Showing results for tags 'crc'.
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Hi everyone, i'm new here, i'm working with plc, but i have unitronics usp-104-b10 on my desk up to now. unilogic version: 1.28.34 I need to solve crc checkum rs485 specific protocol of one noname thermostat. I tried it through message composer but it failed. Thermostat works, I tested it with com debug, connection is ok. Checksum definition: checksum = (header + command + id1 + id1 + data0 + data1 + data2 + data3) and FF xor 3C example: # H30 = (# H0B + # H00 + # H01 + # H00 + # H00 + # H00 + # H00 + # H00) & #HFF xor # H3C it should look like this: txBuffer = 0B 00 01 00 00 00 00 00 30 do you have any idea how to solve it?
Hello everyone. I'm looking for a way to certify that a program running on a PLC is the same as some project file (.vlp). Some type of signature CRC. The tool "VisiDiff" doesn't support V130 nor V350. (the two versions that I use) I've found an SDW value tagged as "Signature Log Checksum", that I think is the key that I need, but this value is always 0, and the help doesn't say anything about it. Can anyone help? Regards, Javier.
Hi, folks. After playing a lot with the PCOM ASCii requests with success I am trying to make binary requests. Here I faced some problems and doubts on the documentation: 1> Example 1 (MI request) states the following values: Header: [0..5] 2F 5F 4F 50 4C 43 -> /_OPLC  00 -> Dest Addr  FE -> Reserved  01 -> Reserved  01 -> Docs says it should be 00 but examples values shows 01 !!! [10..11] 00 00 -> should be all 0s from 09..11 altogether  4D -> 77 decimal "commmand code" [13..19] 00 00 00 00 00 01 00 -> Num of Groups; here I did not understand why the last byte is 00 if the count is 01. Is the byte order reversed in pairs? [20..21] 06 00 -> Data Length also use reversed byte order for "integer"? [22..23] F0 FC -> CRC; any specific byte order? Details: here I found something missing... 00 01 -> num bytes to be read ?? -> missing param FF -> reserved 255 01 00 -> 1st address; reversed byte order? Footer: FE FE -> CRC 5C -> "\" So my question is: despite the missing param in the example (Details -> Oper Type), is there a byte order for addresses and the CRC? Thanks in advance. AD