Concrete pump arm boom pump displacement control, according to the different conditions of the construction conditions to adjust the pumping speed, in the actual operation of great significance. In order to change the pumping displacement usually adopt the following ways, compare as follows: First, the mechanical adjustment by changing manually adjust the throttle opening size, change the pumping displacement. The advantage is low cost, the disadvantage is that you must manually adjust the car, for remote use of pump away from home operations, driving a great inconvenience, and the adjustment accuracy is low. Second, the engine speed adjustment Adjust the engine speed to change the displacement of the main pump, leading to changes in pumping speed, to achieve pump displacement control. Changes in engine speed also change the speed of movement of the cloth rod, in the construction may become irreconcilable contradictions. Third, the electric proportional valve regulation Electronic proportional valve regulation according to the different ways of electric control is divided into the following two ways: 1, the wireless remote control output PWM signal directly drives the displacement control proportional valve wireless remote control output 200-600mA PWM signal Directly drive the displacement control valve to achieve pump displacement stepless speed regulation, to overcome the mechanical adjustment method can not achieve long-distance control problem, the shortcoming is that once the remote control fails, the control panel can not achieve the pump displacement adjustment . 2. Proportional Amplifier Output PWM Signal Drives Displacement Control Proportional Valve The remote control or panel control can easily adjust the input of the proportional amplifier board through the (remote / panel control) switch, so that the proportional amplifier board outputs 200- The 600mA PWM signal drives the displacement control proportional valve. In summary, the proportional amplification board output PWM signal driven displacement control valve to change the displacement of the displacement of the way, not only to overcome the shortcomings of mechanical inconvenience adjustment, but also flexibility to achieve wireless remote control and control panel Conversion control, to achieve pumping displacement stepless speed regulation, more in line with the actual construction requirements.