Cli_DBRead failed with err 665420

[maxgrandi]

I'm using the snap7 library with Siemens 1500 CPU, in my application I have a loop that continuosly read DB from PLC.

The process works for 24 hours continuosly, but this morning it crash.

The return value from DBRead funcion is 665420 (formatted in %d)

I check the "Client Errors Table" but i don't find it. What this value means?

[Davide Nardella]

Hi,
In accord to pag.252 of the Snap7 manual, your error is 0x000A274C,
i.e. an error reported during recv (0x000A0000) and a tcp error 0x0000274C (10060)

The 10060 TCP error is : Winsock Connection timeout.

It means that the PLC closed the connection (maybe due too many concurrent connections)

[maxgrandi]

Thanks,
now I got how to interpretate the error codes.

In my scenario I have only one connection from PC to 1500PLC.
So can be something running on the PC the cause of this issue? Is it possible some socket port conflicts between Snap7 and something other running on the PC?

I read carefully the Snap7 manual and I cannot find anything about the port policy usage.

[Davide Nardella]

No, it's normal that sometime the connection goes out :(
All Siemens equipments and all HMI perform a re-connection if a TCP error occurred.

TCPError = (Return_value & 0x0000FFFF)!=0

Look also at a discussion "Client connected issue" in Bugs reporting.

[maxgrandi]

Thanks for the support.

I'll try to implement some "auto-reconnect" mechanism on my application