serial break on com port does not work

[GeMiTa]

hello everybody:

i have the following problem:

i am writing a command via the '"visa write" vi on the com port of my pc. in some cases the com port does not retun anything. that means that my "visa read" vi would timeout. the problem is that afterwards i need to send more commands but have to break the line in order to be able to do so. I have inserted the "visa break" vi but didn't get the reaction i expected. the line does not break. i tried to increase the break length but that does not work either.

Any ideas?

Using LabVIEW 2013

[Henrik_Volkers · Accepted solution]

A break will not break the connection, it will just put a 1 to the Tx line for a periode longer than 11baud length (?) or specified time. 

A hardware check that the break is send: connect a scope or a DMM to the TX and GND , a 500ms break should be clearly visible even on a 'slow' DMM. (a 10k resistor and two LED antiparrallel  or a handy RS232 minitester would do the same job;) )