I have to REBOOT my computer very thime I use this simple VI

Question

Hi all,
The attached vi is called by another vi when the user wants to know if the [black box] has power. It simply send a command to the [generic a/d..d/a board] which asks the voltage at a certain pin. It works fine! HOWEVER, after I use it, the computer has to be rebooted. I loose communications with the [generic a/d..d/a board]. The only thing I'm doing differently with this vi than the other 20 I have written is Reading the serial port. All of my other programs just write to the port.
Any ideas?
Thanks in advance, this forum is great!
Richard
Attachments:
PowerStat.vi ‏34 KB

Answer 1

Arrow;
Looking at your vi, I have some comments:
- There is no data dependency between the Serial Port Write and Serial Port Read functions. Although you place the VIs one next to the other, that does not guarantee the order of execution, so you may have a race condition in which the read from serial is happening before sending the command with Serial Port Write function.
- I think this command need to be executed only once. If need to confirm, you can place a button to resend the command and then read the serial port. The way is working now is repeating the read/write every 1/10 of a second or so!!
I took the risk to modify your vi to resolve this issues, and the resulting vi is attached. This is only a recommendation.
I hope this is of help
Best regards;
Enrique Vargas
www.vartortech.com
Attachments:
PowerStat_2.vi ‏45 KB