Error messages when connecting to PLCSIM simulator

[denudge]

I try to run any of the examples against a PLCIM Advanced V 4.0 OPC Simulator, but I get the error message:

opcua: uacp: message too large: 1347633490 > 65535 bytes

After tweaking my configuration to use the configs opcua.ReceiveBufferSize(1347633490) and opcua.MaxMessageSize(1347633490), I get another error:

unexpected EOF

I tried to debug the code and drilled it down to TcpDial -> Handshake -> Send “HELF” and then in the following Receive(), it gets 8 header bytes (string "HMMTRASP"), which is parsed to a header having "HMM" message type with the mentioned size of 1347633490. Then, when trying to read the message body with ReadAtLeast() using this size, only 37 bytes are read, followed by an EOF.

Maybe this is a misconfiguration issue of the simulator, but I actually don't know where to start.
I hope that someone could give me any hint.

Thank you in advance
Mathias

[magiconair]

Which version are you using? We recently added client side chunking which should support sending larger messages.

[denudge]

I am using version 0.3.4

[kung-foo]

Are you sure you are connecting to an OPC-UA endpoint? I find it unlikely that any server responds with a 1GB message.

[denudge]

Yes, that sounds really weird, I totally agree.
There is only one setting for the port in PLCSIM, it is called "runtime manager port". The description in the manual says "opens a port on the local machine", for whatever that means. But if I change this port to something else or even disable it (there is a checkbox aside), no connection is started at all. Then, the error differs between "connect: connection timed out" or "read: connection reset by peer" depending on whether I use the simulated ethernet address or just "localhost".