Serial communication, Windows GetCommError

[SysApp]

I am using LabView 6.1 on Windows 98.

I have written a program that communicates with Honeywell UDC 3300 process controllers to retrieve and set temperatures on a heat treat line. I have used it for over a year. Communication is via com1 and a 232to485 converter. I am using the older serial compatibility vi's (serial port init, bytes at serial port, serial port write, serial port read, and close serial driver). I am reading the current temp of each controller about 4 times a minute.

The problem is I have recently relocated and changed computers. I am able to read and write and everything works fine except every few minutes I get "Error -100 occurred at CINLoad- DLL Setup Error Possible Reasons: Windows GetCommError:
The hex value of this code is xFF9C". There is a lot more to it. I have triple checked all connections, resistors, settings, config parameters, etc.

First, does anybody know why I would be getting this?

Secondly, how can I suppress this error? I have disabled all error handlers even in the serial subs. I can not find a VI that is creating this error. Any ideas?

Thanks

[Randy_H]

SysApp,

It sounds like there is an error in the serial port driver in Windows. Those VIs have a CIN at a low level that calls into a Windows DLL. The Windows DLL is throwing an error. Surpressing this error might be hard. There is no direct link to the CIN code, it is internal. You may want to see if you have the latest serial driver files from Microsoft.

I would suggest migrating to using the VISA serial functions. These are much more robust and have much better error checking and handling.

Randy Hoskin
Applications Engineer
National Instruments
http://www.ni.com/ask

[Parks]

I remember a few years ago working with hardware via an RS-232/RS-485 converter and getting these
errors. I eventually traced them down to a bad RS-485 converter.
I also discovered that the self-powered converters were especially prone to spitting out bad data.
Use an externally powered converter and if you are using a laptop, make sure you have disabled all
power saving options in the BIOS. Most laptops lower the voltage at the COM port to levels below
that which a converter can read.




"SysApp" wrote in message
news:5065000000080000003D620000-1031838699000@exchange.ni.com...
> I am using LabView 6.1 on Windows 98.
>
> I have written a program that communicates with Honeywell UDC 3300
> process controllers to retrieve and set temperatures on a heat tre
at
> line. I have used it for over a year. Communication is via com1 and a
> 232to485 converter. I am using the older serial compatibility vi's
> (serial port init, bytes at serial port, serial port write, serial
> port read, and close serial driver). I am reading the current temp of
> each controller about 4 times a minute.
>
> The problem is I have recently relocated and changed computers. I am
> able to read and write and everything works fine except every few
> minutes I get "Error -100 occurred at CINLoad- DLL Setup Error
> Possible Reasons: Windows GetCommError: The hex value of this code
> is xFF9C". There is a lot more to it. I have triple checked all
> connections, resistors, settings, config parameters, etc.
>
> First, does anybody know why I would be getting this?
>
> Secondly, how can I suppress this error? I have disabled all error
> handlers even in the serial subs. I can not find a VI that is
> creating this error. Any ideas?
>
> Thanks

[cilla]

I had a similar problem and I migrated to Visa serial functions but now my application doesn't work in new installations (in other computers). Do I have to add something in the installation files? Do I need some kind of license for use Visa functions?

Thank you

[Dennis_Knutson]

You need to install VISA or VISA run-time on the target computers.

[cilla]

Thank you for your prompt replay

I supose I can not add the VISA run-time in my application without a license, can I?

[Dennis_Knutson]

There is no license required.