Process for regulating a cyclical production of containers by stretch blow moulding from preforms made of plastics material in a machine comprising one or more stretch blow moulding stations, each designed to produce a container during a production cycle, and each provided with a preblowing solenoid valve fluidically connecting the preform to a pressurized fluid source providing a preblowing flow rate (Dp) during a preblowing phase, the regulating process comprising: a) an initializing phase including a step of installation by an operator and of storing of a plurality of operating parameters of the machine during the production cycle, and of regulating parameters including at least one reference template (Ac, Bc, PCab, Fc) of at least one characteristic zone (A, B, Pab, F) of a preblowing curve corresponding to the pressure prevailing inside the preform during at least one part of the preblowing, said reference template (Ac, Bc, PCab, Fc) being determined by a reference time interval and/or a reference pressure interval and/or a reference curve portion, b) a regulated production phase during which, for each production cycle, at least one preform is stretched and blown by injection of a pressurized fluid in each station and during which: - bl) for at least one reference station of the machine, the preblowing curve including the characteristic zone is measured and stored, and a real portion of the preblowing curve is calculated or determined, corresponding to said characteristic zone (A, B, Pab, F) for the measured preblowing curve, and - b2) a new value of at least one operating parameter of the machine is calculated and stored as a function of a difference between the real portion of the curve and said reference template, the regulating process being characterized in that the regulated production phase includes a step b3) of monitoring a possible change, imposed by the operator, of a value of an operating parameter of the machine, the regulating process further comprising a phase of automatically updating the regulating parameter or parameters, which is implemented in the event of an imposed change of an operating parameter of the machine, involving: cl) a stabilizing step during which the production is continued from the parameter imposed during a predetermined stabilizing period, and for each production cycle the actions b1) are executed, and the actions b2) are suspended, and c2) a step of correcting the reference template as a function of the real portion stored during the stabilizing step, in order to continue with the regulated production phase. a) an initializing phase including a step of installation by an operator and of storing of a plurality of operating parameters of the machine during the production cycle, and of regulating parameters including at least one reference template (Ac, Bc, PCab, Fc) of at least one characteristic zone (A, B, Pab, F) of a preblowing curve corresponding to the pressure prevailing inside the preform during at least one part of the preblowing, said reference template (Ac, Bc, PCab, Fc) being determined by a reference time interval and/or a reference pressure interval and/or a reference curve portion, b) a regulated production phase during which, for each production cycle, at least one preform is stretched and blown by injection of a pressurized fluid in each station and during which: - bl) for at least one reference station of the machine, the preblowing curve including the characteristic zone is measured and stored, and a real portion of the preblowing curve is calculated or determined, corresponding to said characteristic zone (A, B, Pab, F) for the measured preblowing curve, and - b2) a new value of at least one operating parameter of the machine is calculated and stored as a function of a difference between the real portion of the curve and said reference template, the regulating process being characterized in that the regulated production phase includes a step b3) of monitoring a possible change, imposed by the operator, of a value of an operating parameter of the machine, the regulating process further comprising a phase of automatically updating the regulating parameter or parameters, which is implemented in the event of an imposed change of an operating parameter of the machine, involving: cl) a stabilizing step during which the production is continued from the parameter imposed during a predetermined stabilizing period, and for each production cycle the actions b1) are executed, and the actions b2) are suspended, and c2) a step of correcting the reference template as a function of the real portion stored during the stabilizing step, in order to continue with the regulated production phase. - bl) for at least one reference station of the machine, the preblowing curve including the characteristic zone is measured and stored, and a real portion of the preblowing curve is calculated or determined, corresponding to said characteristic zone (A, B, Pab, F) for the measured preblowing curve, and - b2) a new value of at least one operating parameter of the machine is calculated and stored as a function of a difference between the real portion of the curve and said reference template, cl) a stabilizing step during which the production is continued from the parameter imposed during a predetermined stabilizing period, and for each production cycle the actions b1) are executed, and the actions b2) are suspended, and c2) a step of correcting the reference template as a function of the real portion stored during the stabilizing step, in order to continue with the regulated production phase.