Have you tried increasing the number of stop bits? In asynchronous serial communication, the number of stop bits (typically 1, 1.5 or 2) controls the amount of time between transmitted bytes. 1 stop bit is the default in VISA Configure Serial Port (Instr).vi. If you increase that to 2, you get one more bit time between bytes. E.g., at a baud rate of 9600, one stop bit = 145 microsecond delay (minimum) between bytes; two stop bits = 290 microsecond delay between bytes.
Note: since the transmission is asynchronous, the sender and the receiver don't need to have the same number of stop bits, since that setting only affects transmitted data. If unit A is much faster than unit B, you could set 2 stop bits on unit A and 1 stop bit on unit B. When unit A transmits, it i
nserts two stop bits between bytes to give unit B more time to process the data. When unit B transmits to unit A, it inserts only one stop bit because unit A is fast enough to handle it.
