Help with Instrument I/O Assistant

[paulwilliams]

I am trying to control an Instrument with 'Instrument I/O Assistant. The control commands that the instrument expects are a ASCII character immediatly followed by a 'nul' character.

If the instrument does not see the null character then it will not run the command. Is there a way of entering a 'null' character as ACSII?

Also with 'Instrument I/O Assistant, What is the termination character \n? What do the termination characters do? 

[Dennis_Knutson]

Unless there have been changes to the assistant in LabVIEW 8.x, you can't use it to send a NULL character. The termination character input is where you tell the assistant to append a specific control character at the end of each command and what character will terminate a read. The only options are \r (Carriage Return), \n (Line Feed), or \t (Tab). You need \00 which is the same as hex 00 and is the ASCII NULL character. You can create an assistant task and then convert to a regular subVI or just use the lower level VISA Write in the first place. There is a couple of shipping examples for serial communication. One has the front panel string control set for '\' Codes Display which does allow you to enter \00. The other sets the termination character with a VISA property node.

[TommyTestBoy]

If you have Instrument I/O Assistant 2.0 or later, you should be able to get this to work by setting your termination character to \00.  You can do this on the Select Instrument Step by selecting the "Termination character" drop down and selecting <custom>.  Then you can enter \00 as your termination character.  On all your Write, Read, and Query Steps, you should now see that your termination character is "\00".

Instrument I/O Assistant 2.x ships on the Driver CD with LabVIEW 8.0, or any Driver CD since LabVIEW 8.0.

-Tommy