Study On Malt Drying Temperature Control System Based On LabVIEW

Dryness is one of an important links in the process of barley malt for easy storage and convenient transportation. Most existing dry systems are based on the MCU to develop. Because of the complicated structural expansibility of hardware and assembly programming of software, they are not strong with the first-class question of form of the display mode. With the development of the modern computerized detecting and control technology, the real-time computer control system of barely malt dryness, based on LabVIEW virtual instrument technology, is carried out.The thesis applies the neural network PID control theory to the temperature control system of the barley malt. According to the operation state of the system, BP nerve network is employed to regulate the parameter of PID controller to reach the optimization in the nonlinear and sluggish time-lag dry system. To make the output state of outputting layer of neurons correspondent to three adjustable parameter k P, k I, k Dof PID controller, and adjust weight coefficient through its study of the neural network, the system steady state is correspondent to PID controller parameter under time control optimally.The hardware part is designed, referring to the actual condition of dry room of barley malt, which is composed of the computer, DAQ card NI USB-6009, temperature transducer, air blower, steady voltage sources and other connecting circuit. The signal outputs the feedback signal after NI USB-6009 gathers the computer to control the frequency converter, thus achieve the goal of controlling the rotational speed of the air blower.The software part is designed to regard LabVIEW8.5 of NI Company as the software developing platform, and the hardware platform of the instrument inserting the card type VI system makes up of transducer, DAQ card, PC. The software part of the systems is composed of the data acquiring, data processing and PID control modules. The temperature data acquiring module is mainly applied to gather the data in dry room. The module of data processing is used for amplifying the gathered signal, and dealing with noise, etc. so as to ensure the accuracy of the signal. PID control module, which adopts LabVIEW control bag and combines PID with neural network technology, is mainly utilized to control dry room temperature.The test results indicate that the system is easy to operate, safe, reliable, easy to maintain etc, and the system is applicable to the actual drying temperature control. The study has more board application prospects in the control process of the industrial and agricultural production.