Viscous material dispensing systems with parameter monitoring and methods of operating such systems

Systems (10) and methods for dispensing or jetting a viscous material (48). The systems (10) include an electronic controller (24) and a jetting dispenser (60) operatively coupled with the electronic controller (24). The systems (10) further include at least one sensor (110, 112, 114) that senses a system dispensing parameter and communicates an output signal representing the sensed parameter to the electronic controller (24) for controlling system operation. In pneumatically-actuated jetting dispensers, a sensor (110) may sense the fluid pressure in the air cavity (66) of the pneumatic actuator. In jetting dispensers (60) with a movable needle valve, a sensor (114) may sense the displacement of the needle shaft (68). In other jetting dispensers (60), a sensor (112) may sense the vibration of the jetting dispenser (60).