Franck,
First of all, the port number should be the (COM Port - 1). So if you are using COM 1 on your system, you would wire 0 to the port number.
Secondly, I recommend that you use the Optomux VI's that ship with FieldPoint Explorer 3.0 (need to do a custom install if you do not have LabVIEW RT 6.0.3). They provide error handling that is not provided in the example that you posted and will prevent problems from serial buffer overflows since you are not reading the receive buffer back for acknowledgement in your example. They can be downloaded (independently of FieldPoint Explorer) from:
ftp://ftp.ni.com/support/fieldpoint/LVFPOpto/
There are two libraries; one of the standard commands and one of the extended commands.
Regards,
Aaron
LabVIEW Champion, CLA, CPI
