serial communication with device

[Jaime Rodriguez]

I have a LabVIEW application which communicates with a Mettler Toledo scale. I have no problems communicating with the device, but I have found that when Windows starts up and the device is connected to the COM1 port, the application cannot access the port. It says that the port is in use. However if I connect the device after the Windows startup routine, everything works fine. I would really like the application to work without having to disconnect the device during Windows startup. (The device outputs weight data continuously ---- maybe this is where windows gets confused with the device).

Anyone have any ideas???

[Jaime Rodriguez]

Is this something I need to modify in the Windows environmente???

[Dennis_Knutson]

On startup, is there another program running that accesses the device? Maybe something from the vendor or a service? When you say you can disconnect it and then get the LabVIEW program to run, do you mean simply disconnecting the cable?

[Jaime Rodriguez]

yES... i MEAN WHEN i Disconnect the cable from the serial prot when Windows startsup. After it startsup I connect the cable to the RS232 port and it works. However, if the cable is connected when it starts up then it says that the port it being used. Like I said, the device outputs data continously.

I checked process explorer and portmon and there are no implicit applications accessing the port.

Any ideas??

[Dennis_Knutson]

I'm not aware of anything in windows that would make an automatic connection to a serial port transmitting data. I hope someone else has an idea.

[Wayne.C]

Building on Dennis' last post, any chance that another application/driver loaded on this PC is taking over the port when it sees the connection or incoming data?  Such as a factory supplied program for the instrument?  Have you tried this on other PC's?

[Jaime Rodriguez]

Not yet... I am going to try on another PC tommorrow. Someone told me it had something to do with /fastdetect entry on the boot.ini file, recognizong the device and thinking that it is a serial mouse>....

Any ideas???