WARNING: RSLinx can "hijack" com1

I posted a problem on another thread and after finding the solution, I thought I would make a seperate thread to give everybody a heads up and help prevent others from having the same problem.

There have been two applications that I have tried to run on two seperate computers, Control flash and a terminal emulation program. Both programs returned an error saying that com1 was taken. Here is todays problem and solution from another post:

"I rebooted the computer and nothing was running - at least in the toolbar. I talked to another engineer at work about this problem and he said that RSLinx has the tendency to "hijack" com1. He was right. I went into task manager and then looked at the processes. Lo and behold, RSLINX.EXE was shown as running but using 0 cpu time. I ended the process and that fixed the problem.

It turns out that RSLINX did the same thing to my desktop. Once it is run, RSLINX.EXE stays running as a process - even if you reboot the computer. The only way to kill RSLINX.EXE is to go into task manager and kill it. I am running the latest version of RSLINX on Windows XP. The engineer said it also happens on other versions of RSLinx and other operating systems."

Not necessarily, in many cases RSLinx Server runs on startup, if it does it will have an icon in the systray. If you do not run it as a server most problems will not occur.

In many cases whether RSLinx is running or not, it can capture the com port, but you may have told it too.




Notice the Reserve Com port for exclusive use by this driver, in some cases this gets checked or is checked by default. The driver that is most noted for capturing the port is the PIC.

RSLinx will automatically start if it is set to run as a service.
You can turn that function off with a check box in the RSLinx Launch Control Panel (Start>Programs>Rockwell Software>RSLinx>RSLinx Launch Control Panel)

Thanks jimbo, meant to show that too.

Another way

Check RSLinx setting in services directory:
Right-click on My Computer, select Manage. Expand Services and Applications, then click on Services. Scroll down until you see RSLinx. Double-click on RSLinx, select disable on Startup type.
This should keep it from loading until it's needed (who active in 'Logix).
My laptop currently has Win2000. XP should be similar.

Mike

This was a big help. Thanks for the info.

RSLinx can still hijack your comm port, even if you don't have it running as a service, and even if the RSLinx icon isn't showing in your ftoolbar.

I have had this happen on a number of occasions. I do not have RSLinx as a service, and it has interfered with Step 7, Concept, and DirectSoft among others.

If you have a suspicion that this has happened, go to My Computer, Control Panel, System, Hardware, Device Manager, Ports, and check out status.

I wouldn't call it a hijack.

RSLinx is only doing what you told it to do. You just might not be aware, or you forgot, that you told it to do that. If you configure a driver for the RS-232 port and you regularly use other applications to access the same port then configure the driver to start manually (startup button in the configure drivers panel). If you configure it to start automatically then it will do exactly that, and then its up to you to remember to shut it down.

I configure RSLix to run as a service and the serial port drivers to startup manually. That way all my ethernet connections are available on demand but the serial port remains available until I specifically start it by clicking the start button in the configure drivers panel. After starting the driver RSLinx does not need to be shut down to make the port availale again. Go to the configure drivers panel, select the driver, and press the Stop button. Do this and running RSLinx as a service won't cause you any problems, it will add convenience.

One other thing to watch out for is RSLinx Enterprise.
If you have it installed on your machine (it is a part of the installation of RSView Studio AKA FactoryTalk View Studio), it can and will take control of your com port if it is configured with a serial driver.

RSLinx Enterprise isn't as easy to shutdown as normal (classic) RSLinx. The best way I've found is to Control-alt-delete, click on processes tab of the task manager, then end the process called RSLinxNG.

Thanks everybody for all the great information. When I get back to work on Monday, I will follow-up on all of this advice. (It is now Sunfday evening -why am I looking at this forum?)

addicted

Electrically_Bound said:

(It is now Sunfday evening -why am I looking at this forum?)

Click to expand...

Because like myself and many here, you are addicted to what you do...

AGENTTINFOIL said:

Because like myself and many here, you are addicted to what you do...

Click to expand...

They say that this first step in getting help for a problem is admitting that you have one. I guess part of the "problem" is that enjoy a large percentage of what I do.

Well I am back at work and I did check and do a couple of things. Apparently it is the default, upon installation, to run RSLinx as a service. I went to the RSLinx startup options box and deselected it to run as a service. Furthermore, I went to the Configure Drivers dialog box and went into the the the startup options for the DF1 driver and set it so that it would only run upon manual initiation.

Thanks for all of the great advice.

Not the best way to shut it down at all. Although we all do it, killing a process like that is a very bad idea, and as operating systems evolve, will become worse and worse.

The proper way to shutdown a service, (RSLinx Enterprise, in this case) is to open up a command prompt, and type "net stop rslinxng". Note that this (as well as the startup, "net start rslinxng" can be commands in a .bat or .cmd file).
It can also be shutdown from the "Services.msc" control applet.

jimbo3123 said:

One other thing to watch out for is RSLinx Enterprise.
If you have it installed on your machine (it is a part of the installation of RSView Studio AKA FactoryTalk View Studio), it can and will take control of your com port if it is configured with a serial driver.

RSLinx Enterprise isn't as easy to shutdown as normal (classic) RSLinx. The best way I've found is to Control-alt-delete, click on processes tab of the task manager, then end the process called RSLinxNG.

Click to expand...

The best, and easiest, way to shut it down Linx Classic, which is what the OP is dealing with, is to right click on the icon in the system tray and select "Shutdown"


Configuring RSLinx to not run as a service doesn't keep you from running into troubles if you first connect to an AB PLC and then try to connect to some other device through the com port. RSLinx, once launched, will stay active until you shut it down. IMO, it is less hassle to just configure your driver to manually start/stop, leave RSLinx as a service, and then be done with it.