TCP OPEN CONNECTION ERROR 63

[jli63]

Hi all,

I had an error 63 while running my case. Basically I build this LabVIEW case as a master station to talk to slave device in Modbus prorocol and read holding register value from it.

The thing is that, my computer can talk to the slave, which I used other monitor software to detect as you can see in 'slave data '. But in labview, I cannot see slave data because of this error.

I am not sure if it is because of something wrong with the code itself. 

Hope anybody who are familiar with implementing Modbus in labview could help me ou!

Thank you!

Jinrong 

[jli63]

I also attached the code and new block diagram to show the error.

Thank you.

[crossrulz · Accepted solution]

Error 63 usually is thrown when there is nobody "listening" for a connection.  Do you have a server waiting for a TCP connection at the IP Address you supplied?

[jli63]

Hi Crossrulz,

Not so sure if the server is listening to request that is transmitted through port 502. But the IP address I entered into the modbus master.subVI is a real relay device and I can receive electric parameter that is mapped in the first holding register through Protocol Test Harness by analyze modbus packets.

So I guess the server does listen to port 502.

What do you think of my coding? Are those modbus subVIs placed correctly as a master station to listen to slave device?

Thanks!

Jinrong

[jli63]

The error just get solved. Reason for this might be the port 502 is occupied by Protocol Test Harness so master in Labview lost TCP connection to the outstation thru port 502.