That's a timeout error. Either the instrument sent nothing or you
specified on your VISA read too many bytes to read and the intrument
didn't send that many. If you're not seeing any characters returned,
verify that you're sending the correct command and that it is properly
terminated. Most serial instruments require that you terminate each
command with something like a carriage return or line feed. If you're
receiving soomething, instead of using a fixed byte count for the VISA
Read, first use VISA Bytes at Serial Port and wire the output of that
to the VISA Read function.
