series communication

[HanTran]

I have a series devices that I can communication with my HyperTerminal but can not able to communication thru Labview and VISA.

I find out that the stop bit setting was not correct.  In the visa interactive control, it detect my stop bit was set at 10 which is wrong.

I tried to set it to 1 but the visa interactive control would do it.

My questions is why I can not set the stop bit to 1 in the interactive control utility? 

Thanks,

Han

[K C]

Hi,

I don't know where you saw the 10 stopbits, but 10 is a bit too much. With the equipment today the number of stopbits is not important. If the COM port is set on 2 stopbits and your device on 1 it will still work OK.

I have never seen more then 2 stopbits.

[Dennis_Knutson]

The value of 10 that you see does set a the number of stop bits to 1. Look at the front panel of VISA Configure Serial Port. The control is a text ring. When the text ring is set to a value of 10, 1 stop bit is selected, When the text ring is set to a value of 15, 1.5 stop bits is selected. When the text ring is set to a value of 20, 2 stop bits are selected. The function was set correctly for 1 stop bit so you need to find another reason why your program doesn't work. Are you sending a termination character with your write string?

[HanTran]

Dennis,

I did not use a Terminator.  I'm new to serial communication.  I was assumming that the visa read/write example will include the terminator at the end.

what is the terminator character that I need to include in my write message string?  I think this is what I'm missing.

I did not know that 10 is meaning 1.  I find it under the visa interactive control.

Thanks,

Han

[Dennis_Knutson]

The terminator is usually a carriage return (\r, x0D), line feed (\n, x0A), or both. Your documentation should say. You can use the concantanate string to add it on the diagram and use the constants on the string palette or you can turn on '\' Codes Display on the string control and type it after the command.