I have to unplug and plug my USB device every time to communicate :(

[ashishchauhan]

I am using a linux machine with an USB port and I have to communicate with a temperature controller which has an UART port and for this I am using a USB to UART Serial Adapter.
port name on my machine is /dev/ttyUSB0

$port = "/dev/ttyUSB0";
open(SERIALPORT,"+>$port") || die("ERROR SENDING DATA\n");
SERIALPORT->autoflush();
 
## in between I am sending data 
 
print $FILEHANDLE $data;
 

and receiving back from that temperature controller ##

after all that process I am closing that file handle.

close(SERIALPORT);
 

code is working fine one time . I am getting correct result .

but when I am trying to run the script second time then it hands at the step when I am sending data to temperature controller

 
print $FILEHANDLE $data;
 

and for this I have to unplug and plug that USB serial adapter again.after that it is working fine.

I am unable to find out what is the problem.
Can u people figure out what may be the possible reasons for it.

Thanks for your reply in advance.

[KevinADC]

@ashishchauhan
What is the filehandle you are using? Is it $FILEHANDLE or SERIALPORT

[ashishchauhan]

oh sorry . it is SERIALPORT .