Abstract: The invention relates to the conducting and to the monitoring, using an automatic machine, of the temperature rise of electrically heated components with which there is associated an identification chart comprising parameters which can be used for conducting and for monitoring this heating, the machine comprising apparatus for reading the chart and for initiating the determined heating program.According to the invention, the chart is divided into a number of zones into some of which are entered, in addition to the said parameters, additional data concerning some of them, the parameters and their associated data are read off using the said reading apparatus, and provision is made for at least some of these parameters to undergo conversions which are induced by some of the other associated zones as a function at least of the data which are contained therein.The invention applies particularly to the monitoring of welding together of plastic components.