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https://issues.apache.org/jira/browse/PLC4X-240?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17181040#comment-17181040
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Stefano Bossi commented on PLC4X-240:
-------------------------------------
Ahhh yes it's difficult to put an elephant in a rabbit hole :-D
I suspected this was the reason because the library 0.6.0 call the PLC two
times, the first one for 220 byte and the second one for 36, as you can see in
the capture; wrongly the 0.8.0 version ask for 256 in a single call !!!
Some magic is always needed for good software to work !
Thanks,
S.
> Protocol error in reading string
> --------------------------------
>
> Key: PLC4X-240
> URL: https://issues.apache.org/jira/browse/PLC4X-240
> Project: Apache PLC4X
> Issue Type: Bug
> Components: Driver-S7
> Affects Versions: 0.8.0
> Reporter: Stefano Bossi
> Assignee: Christofer Dutz
> Priority: Major
> Attachments: Screenshot 2020-08-20 at 09.35.58.png,
> captureString_v_0_6_0.pcapng, captureString_v_0_8_0_wrong.pcapng
>
>
> Dear Christofer,
> unfortunately I have found an another issue.
> Via the HelloPlc app I am trying to read a string from my 1200 PLC; here
> attached you could find the screenshot of the DB as configured in the PLC.
> The command line I am using is:
> {code:java}
> "--connection-string 's7:tcp://192.168.1.192?controller-type=S7_1200'
> --field-addresses '%DB1:6.0:STRING'"
> {code}
> With the library Version 0.8.0 after the patch Julian introduced here: [Pull
> 175|https://github.com/apache/plc4x/pull/175] which fix the reading of Array
> of numbers, the reading of Strings doesn't work any more.
> The error I could read via wireshark is:
> {noformat}
> [Error code: S7 protocol error: Wrong frames (0x8500)]
> {noformat}
> With the library version 0.6.0 the string is correctly read.
> To help you in your work I have attached a capture with both the library
> version.
> Hope to be useful to fix the bug.
> Regards,
> Stefano Bossi
> P.S. just to let you know, I am trying to read a complex DataBlock and this
> is the reason I am experimenting with a lot of different types of variables.
> In the near future I will try to read some many other and to write some too.
> Unfortunately your code is far too complex for my java knowledge and I am not
> able to fix the bug by myself but I could test the library and send detailed
> report if I found some trouble. Hope this could help anyway.
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