What is the difference between doing a VISA read asyncronous vs syncronous?

[Ben]

If I pass a byte count of say 10 to the VISA read configured as syncronous and there are less than that number of bytes waiting at the serial port, Will the node wait until the required number of bytes show?

Support just got done telling me that the whole LV app will hang until that number of bytes have arrived. Is this correct?

The time out is set for 10 seconds and I have disabled the termination character.

These are serial reads.

Ben

[DiegoF]

Hi,

That is pretty much it. The Read VI will wait until the timeout expires and return whatever found in the buffer, or until the buffers has the requested numbers of bytes. A termination character would avoid this.

Check the following discussion. Although it's about asynchrnous read, you might find it interesting:

http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=506500000008000000F3460000&UCATEGORY_0=_201_%24_13_&UCATEGORY_S=0

DiegoF.
National Instruments.