rs-232 visa with hardware handshake

[gdped]

The Visa driver does not seem to control the handshaking properly.  I send a block of data and the VI does not hold off when the receiving device asserts a negative ready to receive. 

[RavensFan]

I've done a lot of work with serial communications, but very rarely have I had to worry about handshaking.  Let me ask a couple questions.

1.  Where did you set the handshaking to hardware control?  Are you sure it is turned on?  (Try checking the property node of the serial port in the code to be sure.)

2.  How large is your buffer and how many bytes are you sending?

3.  You say the "VI does not hold".  Do you mean the code is not pausing at the VISA write while the handshake line is set?  Maybe its not supposed to.  I would think that once the code has written all of its data to the serial port buffer, it would consider its job done and move on to the next step.  While the handshaking lines would control the transfer of data in and out of the buffer to the data lines.

4.  Are the VISA reads and writes set to "synchronous" or "asynchronous".

[satman41]

I am also having an issue with hardware handshake on rs232 serail ports.

When testing ports that use hardware handshaking, if the hardware handshake doesn't occur, labview waits until it recieves a one ( no timeout, no error, I've waited hours)( timeouts are all set to 10 seconds). the only solutions I've found is to unplug the bad cable and plug in one that works properly, or reboot the computer.

The only thing I haven't tried is to put all my port reads in a timed loop and close the port if it times out. Does anyone know if this will solve the problem, or will labview's visa serial read still hold the port until it gets a handshake?

Does anyone know a fix or work around?

[RavensFan]

Post your code.  The VISA Read should timeout no matter what the state of the hardware handshaking lines.