Method and system of controlling a plant for dehumidifying and/or drying

A method of controlling a plant for dehumidifying and/or drying plastic material in granular and/or micro-granular and/or powder and/or flake form, said plant comprising a process fluid generator and at least one dehumidifying/drying hopper intended for feeding a respective user machine associated with said plant, the user machine for treating and transforming a plastic material, the user machine including a melting device for melting said plastic material and a moulding device for moulding, by injection moulding and/or blow moulding and/or compression moulding said plastic material the system includes a control and management unit configured for:

• receiving a signal, detected by a measurer in said user machine, corresponding to a value of an injection pressure (Ppwp) of said plastic material in melted state;
• verifying whether the detected value of said injection pressure (Ppwp) is greater than a preset limit value (Plim) of said injection pressure (Ppwp);
• and
• sending command signals to said process fluid generator for adjusting, if said detected value of said injection pressure (Ppwp) is less than or the same as said preset limit value (Plim), a process parameter of said plant;
• the method of controlling includes the steps of:
• detecting in said user machine the pressure (Ppwp) of said plastic material in melted state;
• and
• adjusting at least one process parameter (Dp) of said plant on the basis of the detected value of said pressure (Ppwp) using the control and management unit.