Control System Design Of Dual Functional Pharmaceutical Packaging Machine Based On PLC

The pharmaceutical packaging system can not only improve the productionefficiency, product quality and system performance, but enhance the system reliabilityand safety. And it is convenient to maintain and debug. A more automatic packagingprocess becomes critical as the Current Good Manufacturing Practices (CGMP)requires the improvement of production process control. Aiming to improve theefficiency and realize dual functional packaging, this project has been carried out tostudy the intelligent drug packaging system based on actual demands.In this paper, the working principle, control requirements and working process ofpharmaceutical packaging machine are analyzed in details. The hardware andsoftware of the system are designed to realize drug packaging functions. S7-200SMART PLC is used as the master controller, which realizes complicated control ofservo drive, air cylinder and other controlled objects and signal acquisition ofdetecting elements such as photoelectric sensors, proximity switches, encoders and soon. SMART700IE touch-screen, as the human-computer interaction interface hasfunctions of displaying, monitoring and giving an alarm. The communicationsbetween control layer and monitoring layer are accomplished by Ethernet, realizingthe controllability and visualization of packaging process. Drug packaging machine ismade up of six parts, including drugs transferred into delivery-cells, instructionssuction, boxes suction, boxes packing, counting and eliminating unqualified drugs. Itrealizes the automatic control by advanced technologies, such as PLC control, PIDcontrol, servo control, sensor detection, and man-machine interface display.Pharmaceutical packaging machine for dual functional design, achieves the fastpacking for both medicine plates and medicine bottles. When packing materialschange, the corresponding packaging mold also needs to be changed. Plate and bottlepackaging process are integrated when the software is designed. The packaging formis chosen through the man-machine interface, which improves the versatility andefficiency of the packaging machine. At the same time, in order to realize thequickness and accuracy of elimination process, the pressure in the air cylinder isanalysed and the PID algorithm is used in pneumatic control system. Air compressoris controlled by frequency converter and motor, keeping the pressure stable in the cylinder.This system has benefits of reasonable structure, accurate device selection,precise control, regular wiring and friendly human-computer interaction interface. Thetests show that the system has an accurate count, can pack170boxes per minute, andget rid of defective products accurately. It turns out to have a stable running and meetthe design requirements.