Problems with serial Baud rate

[tengels]

When trying to communicate over a serial port I get "port settings conflict" error in the MAX.

After selecting the correct serial settings (57600 Baud, 8bits, no parity 1 stop bit) and saving the port settings the device still doesn't working correctly.

As I open a VISA session in MAX I see in the "View all settable Atributtes...." that the baudrate did not changed to 57600 Baud. Only when writing in the VISA session the correct baudrate with the property node (write) the communication for that session works.

However when refreshing the MAX or leaving the MAX the settings are changed back to 9600 baud.

When programming in LabVIEW I can't get a reply back. It looks like that the application uses the wrong baudrate.

(Used several examples from NI where baudrate is configured.)

Does some one encounderd this problems before and is there a work arround for it?

I'm using LabVIEW 8.5

MAX 4.2.1.3001

NI-VISA 3.1

Hope someone could help me

Theo

[shoneill]

QUOTE (tengels @ May 14 2008, 01:52 PM)

Hope someone could help me

Theo

I think MAX defaults to the windows default settings. I never use MAX to configure a serial port. I always do it in code. YOu never know what state a port was left in from a previous "owner".

You should set all neccessary serial port options in code, and this should work. MAX is, IMHO, not very useful when testing serial ports.

What are you trying to get a reply back from? You only mention your program. What yre you communicating with?

Shane.

[Rolf Kalbermatter]

QUOTE (tengels @ May 14 2008, 07:52 AM)

When trying to communicate over a serial port I get "port settings conflict" error in the MAX.

After selecting the correct serial settings (57600 Baud, 8bits, no parity 1 stop bit) and saving the port settings the device still doesn't working correctly.

As I open a VISA session in MAX I see in the "View all settable Atributtes...." that the baudrate did not changed to 57600 Baud. Only when writing in the VISA session the correct baudrate with the property node (write) the communication for that session works.

However when refreshing the MAX or leaving the MAX the settings are changed back to 9600 baud.

When programming in LabVIEW I can't get a reply back. It looks like that the application uses the wrong baudrate.

(Used several examples from NI where baudrate is configured.)

Does some one encounderd this problems before and is there a work arround for it?

I'm using LabVIEW 8.5

MAX 4.2.1.3001

NI-VISA 3.1

Hope someone could help me

Theo

What is the serial interface? A USB to Serial converter? If so it may be a problem in its driver which VISA does not know how to deal with properly. I've seen strange behaviour with several USB to Serial adpaters in the past.

Rolf Kalbermatter

[orko]

QUOTE (shoneill @ May 14 2008, 07:54 AM)

I think MAX defaults to the windows default settings.

I agree with shoneill on the MAX issue. After you change the Windows port settings from within the Windows device manager you should see MAX default to the new changes. I also agree that it is good practice to rely on the code, not MAX for proper configuration of your serial port.