HMI and Laptop to PLC via Serial Port

I get service calls to companies who have bought skid package equipment and have touch screen control only hooked to a MicroLogix series controller. Then I can't hook up my laptop to troubleshoot a problem via the serial port. Have any of ya'll ran across this and is there a work around? I know I can unhook the touch screen and go from there but I may need to only "monitor" a problem or process for a period of time while the operator continues to interface with the PLC.
Thanks,
Dog

Here are a couple of solutions.

http://www.tomantron.com/applications.htm

I used one of these on my last project:

http://uk.rs-online.com/web/search/searchBrowseAction.html?method=getProduct&R=537-7169

Did not come with leads, but the manual shows you whats needed. It does not make really clear (even in the manual) that you can put this on a micrologix, connect an HMI, and also use the 9way d plug at the bottom to go online with the PLC whilst the HMI still runs ok. Beleive me it works!

OK, mickey beat me by one minute!

Thanks Guys, this Message board never fails! The knowledge here is limitless!
Thanks Again

Your Welcome