Labwindows RS232 Library limits

[niico]

I'm facing an issue under Labwindows CVI 2010 with the RS232 Library I'm using. The highest baudrate is limited to 256000 whereas we are currently using 460800 baudrate. Then when using RS232 library an error is occuring because the baudrate is out of range.

I would like to know if an updated RS232 library can be downloaded or if we have to modify the current library.

If a new library is existing could you let me know where I could find it.

If we need to modify it, let me know where I should find some tutorial to modify libraries.

Thanks in advance.

BR,

Nicolas

[Wolfgang]

You might want to consider the VISA library: viSetAttribute (, VI_ATTR_ASRL_BAUD, );

The VISA specification allows for any BAUD rates to be used in specifying a serial port's speed of transmission provided the driver itself supports non-standard BAUD rates.

[ebalci]

I know that I can set the baud rate to 1,500,000 (1.5 Mbit/s) without any problems using CVI 8.5.1 and 9.0.

We have test stations currently and actively working with such settings. They have special high speed communication cards in them.

I dont know if CVI 2010 has a different RS-232 libary than previous versions.

Actually, I would really prefer NI engineers in the forum to enlighten us about this.

[Kobi_K]

As S. Eren BALCI said I've also used the RS-232 Lib for high rates up to 6M/s and it worked on CVI 9.1

one comment is that pay attention if you changing the baud to high rates you need to set it's internal clock in the device manager to a match clock.

[niico]

First of all thanks for your reply.

In fact, after deeper investigation, I have seen I was using FTDI USB serial interface and not RS232 interface anymore.

So I should have to use FTDI library but for the moment I haven't seen how to use it in my projects. If you have any idea this is welcomed.

Thanks

Nicolas

[ebalci]

Actually, it does not matter which form factor you use.

You can have PCI, USB, PXI, etc ports.

If you successfully introduced the hardware to the operating system, they all finally become a "COM port" with a port number assigned by Windows.

You can see that from the Device Manager.

After that point all you need to do is provide the correct port number and settings.

All the rest is handled by CVI RS-232 library and Windows itself. You don't have to deal with FTDI drivers or anything such low level.

Hope this helps,

[Wolfgang]

Hi Eren,

I think one has to deal with the driver a little bit: one should verify that the driver actually supports the desired non-standard BAUD rate...

[niico]

OK for RS232 library but when I'm opening OpenComConfig file of RS232 library I can see that the maximum baud rate defined is 256000. So I'm wondering where I could find a more recent RS232 CVI library.

Thanks and regards,

Nicolas

[Wolfgang]

Nicolas,

This is the maximum pre-defined BAUD rate - in the help associated with this function you will also find:

You can use nonstandard baud rates. All baud rate values are interpreted literally by the comm driver.

Obviously, as stated by Eren and Kobi, you can use higher rates - as long as the driver itself (provided by the manufacturer of your port hardware) supports non-standard BAUD rates.

[ebalci]

Nicolas,

That is not an actual limit.

You can manually type any (of course should be supported by the hardware) baud rate value after you insert the function call into your source code.

The limit you see is set by the function panel, not the library itself.

Actually, if you press Ctrl + T while the baud rate control is selected in the function panel, you will see that it turns into a box type control in which you can type your desired baud rate.

As Wolfgang suggested, you should make sure the hardware supports the baudrate.

Please read the hardware manual carefully to see if any operations are required to reach thos rates.