A general identification procedure is given, for first and second orders plus time delay models, that uses two or three arbitrary points over the process reaction curve. Two simplified versions of the methods are described: the three points 123c identification method that uses the times required to arrive to the 25, 50 and 75% of the output total change, and the symmetrical method that uses points symmetrically distributed over the reaction curve. It is also described the use of the identification methods to obtain the optimal times for the model parameters identification. Using an example, the goodness of the models identified is compared.