serial communication

[n 516]

I am using �Serial communication.vi� to communicate with a RTE-140 bath/Circulator (from NESLab). It works well (write and read). Now, I need to write from a file. So, I replaced �Visa Write� function by �Visa Write from File� function in �Serial communication.vi�. I specified a file at filename terminal. Let�s give this new vi a name �Serial communication from file�. Then, I ran this vi. I can �write�(such as set a setpoint). But �read� doesn�t work (such as read setpoint). It gave me a warning (possible reason: the number of bytes transferred is equal to the input count). Also, �write� only works once. If I run it second time, it doesn�t work. Please help.

[Randy Solomonson]

It is likely that a set of VISA writes and VISA reads are necessary to control this instrument. Also, be sure that the end-of-string (EOS) character is set properly. Note that in a Windows test file every time is pressed a carriage-return and line-feed are entered.

[Rob Cole]

Try doing a VISA Close before trying to do an input from the instrument. VISA read will re-open a VISA session. You might try forcing LV to close the file as well. Did you specify how many bytes you are expecting in the VISA read? The default is 0, which does not help much. Also ensure that the bytes to read number is not too high, or the VISA Read VI will time out.

Rob