COM Problem

[Bocce Player]

A ni-PCI-232/4 was recently installed in a HP Workstation computer with XP.  The 'ni' code runs on the previous DELL computer.

I have three of the four ports connected as Com_1, Com_2, and Com_7.

Only COM_1 is having problems.  Com_1 sends a command to reboot the UUT and waits for a reply. 

Com_1 does not see a valid reboot command , thus times out.  This is part of a test protocol and I do not have control over the 'vi'.

Can anyone GUESS...?   Do I suspect a noise or timing problem ?   The other two COMS are O.K.( maybe safe to rule out ground loops or noise)  

THANKS !

[Dennis_Knutson]

There could be any number of problems. Have you verified that the com port is listed in windows device manager? If the program is using VISA to do the serial communication and if you have MAX (Measurement & Automation Explorer) installed, it should be listed there as well. With this program closed, can you connect to the UUT with Hyperterminal and test the command? Do other commands work? Have you tried a different cable? Saying 'ni' code is very vague. What exactly was the program developed with?

[Henrik_Volkers]

Are you shure that you have connected the right com ports?

My guess: Port 1 and 2 are the build in PC ports ,  3 is a softmodem, so 4,5,6,7 are the NI card.

I have a tool similar to this:

(My one has some switches to toggle Tx,Rx lines , loop back etc.)  Quite handy to solve problems in the field. You can see if the port is correctly adressed.

Here a McGuyver 😉 for a quick loopback test.  This shortcuts the Rx and Tx line so you should be able to read what you send.   (At own risk!)