232 still going whilst using TCP.

[Ausman]

Hi again all,

today I was working with another brand of plc hooked directly into my system with 232.  During the course of events I was checking remote site operations using Remote Access running on TCP Call.  As I closed the session up popped a request box saying "Do you want to close the modem connection?"  Huh? What modem?

After a bit of puzzling I realised it was the other plc on the serial line making the strange shutdown happening, with Remote Access thinking there was a modem there.  I turned it off and the problem went away.  But it does give rise to the question as to why Remote Access was even looking at the 232 line, when I was only using TCP.  If you do the same thing in Visi, it shows the "modem connected" box whilst opened.  I know this scenario is a bit unusual, but perhaps there is something wrong in the connection area of the program that needs looking at.  To my thinking, if you are only using TCP, and your programs open to those settings as default, why is Visi/RA/etc still monitoring the serial com port?  It/they shouldn't even be thinking about it!

cheers,

Aus

[Flex727]

I'm having a similar problem with VisiLogic version 9.8.31. Whenever I try to communicate with the PLC with a serial connection, the Modem box pops up and the connection fails.

[Ausman]

Hi Flex,

that's a strange one.  I have no trouble like that, but I am still using 9.7.55.  However, have you been using other PLC maker's programs?  Rockwell in particular was exceptionally good at stuffing up/taking over without asking/wrecking a perfect system/you get the idea my 232 port settings.  I'd uninstall all your com ports and ensure that the driver used during reboot and discovery is the standard one for your ports and m/board, then try again.  And make sure through task manager that nothing else is running that could be using the port...some of the other programs' services are an auto startup.

From memory you also use  Version Swapper, so have you tried an older Visi to see if it works ok?

And for the creators, I have since checked the event log in Visi and there in the record is evidence of every start of the program opening the 232 com port and immediately closing it again. 
So I'm assuming that RA does the same thing.  Why does it do this?  It is obviously why my problem occurred.  It shouldn't open any port until requested.

cheers,

Aus