sub OPCItemRead {

	my $groupdata = shift;
	my $itemno = shift;
	
	my $items;
	my $data;									# reference to the hash of data returned by Read()
	
	$items = $groupdata->{grouphandle}->OPCItems();

	$data = $items->Item($itemno)->Read($OPCDevice);
	
}

sub OPCItemWrite {

	my $groupdata = shift;
	my $itemno = shift;
	my $newvalue = shift;
	
	my $items;
	
	$items = $groupdata->{grouphandle}->OPCItems();

	$items->Item($itemno)->Write($newvalue);
	
}