Pneumatic master module for pressure or flow proportional control, comprising: - a master module valve body in which passages for a flow of pressurized air are formed, said passages connecting a master pneumatic inlet port to a first master pneumatic outlet port for a direct pneumatic connection to a load and to a second master pneumatic outlet port for the pneumatic connection to a pneumatic inlet port of a slave module which can be connected to the master module; - a master proportional electrovalve adapted to supply the first and second master pneumatic outlet ports with a regulated flow of pressurized air entering the master module through the pneumatic inlet port; - an electronic control unit configured to implement a digital communication bus interface for data exchanging with other master modules; the pneumatic master module being characterized in that it further comprises: - a relative pressure sensor for detecting the pressure of the regulated flow of pressurized air downstream the master proportional electrovalve; - a master male-type inlet electronic connector and a master female-type outlet connector for receiving and transmitting analog and digital electronic signals, and in that - the electronic control unit is adapted to drive the master proportional electrovalve and a slave proportional or on/off electrovalve of a respective slave module according to a pressure signal provided by the relative pressure sensor; - the relative pressure sensor and the electronic control unit are mounted on a master electronic printed circuit board, the master male-type inlet electronic connector and the master female-type outlet connector being mounted on parallel opposite sides of the master electronic printed circuit board. - a master module valve body in which passages for a flow of pressurized air are formed, said passages connecting a master pneumatic inlet port to a first master pneumatic outlet port for a direct pneumatic connection to a load and to a second master pneumatic outlet port for the pneumatic connection to a pneumatic inlet port of a slave module which can be connected to the master module; - a master proportional electrovalve adapted to supply the first and second master pneumatic outlet ports with a regulated flow of pressurized air entering the master module through the pneumatic inlet port; - an electronic control unit configured to implement a digital communication bus interface for data exchanging with other master modules; - a relative pressure sensor for detecting the pressure of the regulated flow of pressurized air downstream the master proportional electrovalve; - a master male-type inlet electronic connector and a master female-type outlet connector for receiving and transmitting analog and digital electronic signals, - the electronic control unit is adapted to drive the master proportional electrovalve and a slave proportional or on/off electrovalve of a respective slave module according to a pressure signal provided by the relative pressure sensor; - the relative pressure sensor and the electronic control unit are mounted on a master electronic printed circuit board, the master male-type inlet electronic connector and the master female-type outlet connector being mounted on parallel opposite sides of the master electronic printed circuit board.