public void escribeArchivoINST(int lin, String etq, String cod, String ope, BufferedWriter bw){
    	String line;
    	line = Integer.toString(lin);
    	try{
    	    bw.write(line);
    	    bw.write("\t ");
    	    if(etq.isEmpty())
    	    	bw.write("Null");
    	    else
    	    	bw.write(etq);
    	    bw.write("\t ");
    	    if(cod.isEmpty())
    	    	bw.write("Null");
    	    else
    	    	bw.write(cod);
    	    bw.write("\t  ");
    	    if(ope.isEmpty())
    	    	bw.write("Null");
    	    else
    	    	bw.write(ope);
	    	bw.newLine();
    	}catch(IOException ioe){}
    }