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Failed reading DataTables structure from PLC


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Good morning,


I use .NET driver dll since 2011 to communicate between our software and several PLC.

Recently, we move the server (on wich our software run)  from Paris (France) to Hambourg (Deutshland).

PLC still remains in Paris.

Server ask every 10 seconds all the PLC and sometimes I have an issue (almost 1 per hour) :


"Failed reading DataTables structure from PLC. Details :

Source array was not long enough. Check srcIndex and length, and the array's lower bounds"  Source : Unitronics.DataTables


This error never occured before.

TimeOut may be the cause ?


Versions are as below :

Unitronics.DataTables.DLL ( and Unitronics.ComDriver.DLL (


Thanks a lot for your help

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You can try increasing the timeout, maybe it will help (but my guess that it will not).

Maybe once in 10 seconds is too much (since you are connecting to several PLCs). You should consider the latency.

Reading the structure and values probably requires several packets to be sent from and to the PC, and since now the distance from the PC to the PLC is larger, then the request might not finish in time. (And maybe several requests in the Data Tables DLL are mixing)

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