Without knowing what hardware you are using, your wiring setup, nor what you are communicating with, it will be difficult to provide specific advice. However, the error number you are receiving is typically associated with a timeout indicating that the VISA Read function did not receive the requested number of bytes in the time you allocated to it. Several simple mistakes can cause this behavior. Generic debug information below:
Why Do I Receive Timeout Error -1073807339 on VISA Read or Write?
Regards,
spex
Spex
National Instruments
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