Getting error code -251723766 returned from the "EthernetIP Open Session.vi" while trying to talk to a PLC

[tjmiller]

Hello Lewis

  Yes. I did get a response back from my co-worker in California.

  He said that the PLC development S/W is on a totally separate PC.

  In other words we have 2 different PC's in California, 1 with the PLC development S/W and 1 with the LabVIEW .exe file that I am working on.

  As you suggested I also created and sent to my co-worker out in California an extremely simple LabVIEW program that only attempts to read a single boolean value from the PLC. 

  My co-worker in California ran this extremely simple .exe program yesterday and sent me back a screen capture of the error message that was generated.

  This screen capture has been attached to this posting. The filename is "SimpleEthernet_IP_WriteBooleanTest Startup.jpg"

  The error message is the same one we get when we try to run the full blown application.

  The error message is:

  "CIP Error - Extended status may be available"

 CIP Status: 0x1 (connection failure)

 CIP Extended Status: 0x311 (Port not available)

I have several questions:

  Does the error message "Port not available" mean that some other piece of S/W on the WIN7 machine is using the Port number?

  Are there any diagnostic programs we can run to see with port numbers are being used and by what program on our WIN7 machine out in California?

  As it stands now we have no ability for the PC to communicate with the PLC and this is delaying a million dollar project here at Rockwell Collins.

  Please let me know if you see anything wrong with the simple LabVIEW program that I created that does nothing more than call the "EtherntIP Tag Write.vi"

  Thank you

[LewisL]

Hi Todd,

From this page, I think the same error code does mean as it's suggested - port not available.

Please use Wireshark (a free software for packet capture) to catch the whole erroneous communication. The capture file shows everything a packet contains, including port number.

You can also find out which program is taking up which port by input commands in the Windows cmd (netstat -nb). There should also be certain small tools for it as well.

If you need help, you can post your capture file here, too.

You can post the block diagram of your simple text VI as well. A front panel screenshot does not tell alot.

Thanks.

[tjmiller]

Hello

  When I tried the "netstat -nb" command as you suggested in your prior posting, I get an error mesage back from Windows that says "The requested operation requires elevation"

  So instead I used the "netstat -a -n -o" command.

  The output of the "netstat -a -n -o" command is attached to this posting in the file  named "netstat_output#1.txt"

  Also a screen capture of the task manager output showing the process ID's is attached in the file named "TustinComputer_TaskManagerScreenCapture#1.jpg" 

  I have also attached a screen capture of the block diagram for the "ALR_Write_Boolean.vi" LabVIEW module.

  Can you review the output of the "netstat -a -n -o" command in the attachment and tell me which program on the PC is causing the "Port not available" problem?

  Thank you

[tjmiller]

Hello

  Did you see my previous posting from 2-18-2015?

  Please respond as we are still not able to get the PC to communicate with the PLC using the Ethernet / IP S/W.

Thank you

Todd J. Miller

Rockwell Collins

Flight Control Systems

319-295-8689

[Aix-La-Chapelle]

Hi TJMiller,

LewisL is out of office, apologies in the delay in response.  

It looks like he had requested a wireshark capture so that we could take a look at this information.  Were you able to perform such a capture?  We will be able to use this wireshark capture to see everything the packet contains including the port number.  

I will discuss this further with him to get a better idea of where we are with troubleshooting.  I apologize for the delay.

[LewisL]

Hi Todd,

I received your capture file. The capture is pretty simple -

#3~5 established a TCP connection using the correct EIP explicit port 44818, then

#6 #7 shows the session is registered successfully.

The PLC in #9 directly gave a failure - port not available to #8's send request. 

I don't know why PLC did this from this capture. Normally a PLC would return data in this step.

I suggest that you or the PLC's technical support check why the PLC's port became unavailable. I think it's about the PLC usage/ setting, rather than other parts of the network.

[tjmiller]

To NI Tech support

  This problem where we could not communicate with the PLC at all has been fixed.

  I misunderstood the error message "port not available"

  I thought that meant an Ethernet port was not available.

  What it actaully meant was that we had an addressing error in the network configuration string.

  I had "10.0.0.3,0,0" when I should have had "10.0.0.3,1,0"

Thank you for your assistaance

[LewisL]

Thank you for the update, Todd. I'm glad you worked it out. Sorry, the CIP extended status:0x311 (por not available) got me into thinking that it was the TCP/IP port even by reading its description.

Now that we know, and I'll make a proper knowledge share for it.

Thanks again.