sub FT_OpenPM{
    my ( $self, $devNum ) = @_;
    my $status = $self->{'FT_STATUS'};
    my $handle = $self->{'FT_HANDLE'};
    #import function
    my $fct_open = new Win32::API( 'FTD2XX', 'FT_Open', 'IP', 'I' );
    unless( $fct_open ){
        print("FT_Open not found!\n");
        return 0;
    }
    #call imported function
    $status = $fct_open->Call( $devNum, $handle );
    $handle =~ s/\0.*$//;
    #$handle = Storable::retrieve( $handle );
    #return the functions return status and the handle
    return ($status, $handle);