Serial Port On Windows Xp Vs Windows 98

[ianbuckley]

I have an old DOS based program that I use for a small PLC manufacturer. The program runs fine on Windows XP Pro SP2, other than the serial port update rate is really slow when online or downloading a program, which causes revision information to be lost on the download. They have a Windows 2000/XP version of the software, and it handles the revision tracking problem, but it lacks some of the troubleshooting tools that came with the old DOS stuff. I asked the guy who wrote the Windows version of the software and he said that Microsoft handles the serial port differently on Windows 2000/XP than DOS and Windows 9x did. Something about time slicing the serial port, so that it doesn't update all the time or something. This causes the old troubleshooting tools to not work properly. So we keep old Windows 98 PCs around just to be able to run the old DOS version of the program. Does anyone here know anything about this serial port issue, or perhaps a way to reconfigure how Windows2000/XP handles the serial port so that it could work the way it did for Windows 9x? Thanks, Ian

[TimWilborne]

Can you specify what software you are talking about. It might help us more

[ianbuckley]

The software is for programming PLCs from Systems Engineering Associates in Colorado. They make compiled PLCs that are often used for high speed front ends of control systems. They have sourcing transistor output cards that are rated at 8A continous and configurable timed interrupt from 0.25ms to 10.0 ms. They are primarily used in the can manufacturing industry. SEA is a small company without a huge engineering staff to work on the software, and most of their customers view the high speed front end as a black box. So spending a lot of resources on software is not a high priority. The software works fine for creating stable programs, though it is not as user friendly as some of the stuff from larger companies. On the other hand, there aren't any significant bugs in it either. The software has on-line monitoring capability and upload and download much like any other PLC software. The serial port handling worked perfectly well for systems that supported DOS (until Win2000 in other words). However, Microsoft changed something about how the serial ports were handled in Windows 2000 which carried over to XP. I was just wondering if anybody here happened to know anything about how the serial port is handled differently in 2000/XP, and if there is a way to make the serial port act as it did with Win 98. This might not be the right place to ask this question, but I thought I'd try. Thanks, Ian

[Spanner]

We had an issue with taht too causing comms problems between a Yaskawa Progic 8 and YPSU (Dos Based). The solution was eventually to make the Systems Dual boot and hav one running pure DOS on one boot but Windows on another. Not sure if that's any good for you but is you find out anything about setting the Comm ports to run faster in XP, I'd love to hear about it! Dual boot is a bit of a pain.

[Mickey]

Right click my computer,click properties,click hardware,click device manager,expand port, double click com 1,click port settings,click advanced There are some slide bar settings you might play with to see if they help.