Application And Development Prospect Of PLC In Freeze-Drying Production Line Pharmaceuticals

Part 1 Operation Principle Of Programmable Control Technology

According to the number of I/O points of programmable logic controller (PLC), it can be divided into three types: small computer, medium computer and mainframe. Although there are many types of PLC, their structure and principle are basically the same. Internally store user-oriented operation commands such as logic operations, sequence control, timing, counting and arithmetic operations, and control various types of machinery or production processes and related peripheral devices through digital or analog input and output It forms a whole with the industrial control system, so as to achieve the purpose of control. The structure of PLC mainly includes CPU, memory, power supply, dedicated input and output interface, data bus and so on. PLC first converts the continuous action of the filling machine into a programming language, then inputs and outputs the controller according to a certain algorithm, and then the corresponding components receive the signal from the controller to make corresponding physical actions, so that the pharmaceutical equipment production line can be automated.

Part 2 Main Application Of PLC In Production Line

As the core component, PLC collects switching signals from various photoelectric sensors or limit switches, and analog signals such as pressure, temperature, liquid level, and flow to control the main motor, electric heating tube, peristaltic pump, and various solenoid valves.

1 Application Of PLC To Bottle Washing Machine

Oven mesh belt lacks bottle high speed, dynamic production at half speed, full bottle shutdown graded control host speed; injection water temperature, water pressure and compressed air pressure lower limit alarm and shutdown; low liquid level stops circulating water pump; bottle output counting; host Overload stop and prompt.

2 Application Of PLC To Filling Machine

No-bottle stopper, no-bottle stopper, on-line sampling, production count, lack of stoppage alarm, stoppage due to lack of bottle. In case of overload or emergency, the equipment can be shut down immediately, and after troubleshooting, the start button needs to be pressed again to resume production. It runs online with other equipment, and when there are too many bottles in the front bottle unscrambling table, stop the bottle conveying belt of the oven and the bottle washing machine.

3 Application Of PLC To Oven

Connect the touch screen to read process parameters; control the speed of the mesh belt motor and each fan through the frequency converter, and monitor the operation of each fan, such as overload and low wind speed damper position; PID controls the temperature of the heating pipe, and detects the heating pipe and preheating section , high temperature section, cooling section temperature; connect the printer to print the data or curves recorded in the production process.

Each equipment on the production line. Only the I/O signal of simple limit transmission is used to control the start and stop. In fact, it is only an independent unit, and the degree of automation is relatively low. It is necessary to continue to explore the computing and remote communication functions of PLC.

Part 3 Process Requirements And Development Prospects Of PLC Application In Pharmaceutical Equipment Due To GMP Upgrade

The new version of GMP has three major target elements for equipment requirements: to minimize human error; to prevent drug pollution and reduce quality; to ensure a quality management system for high-quality products.

The structure of the equipment is generally fixed, and once it is put into use, it is almost impossible to change it. For example, in the design of the heating section of the oven, the number and specifications of the heating tubes are difficult to modify after use. If the uniformity of heat transfer and heating is found to be poor during use, the temperature curve will change significantly. Make necessary adjustments to the fan frequency and PID adjustment parameters. It has become a new trend that the equipment can automatically record and adjust the heating, which puts forward higher requirements for the developer of the PLC program. Modern fuzzy algorithms are added to the PLC program to make it control the heating tube to achieve a dynamic balance. Drugs are in direct or indirect contact with production equipment. In drug preparation, the structure is usually designed to facilitate the flow, displacement, reaction, exchange and cleaning of materials. Electrical control needs to cooperate with the process, and there are clean area shifts and large spans in the monitoring of such production steps. The ideal solution is wireless transmission, which wirelessly transmits the data measured by various secondary instruments to the host computer In , the host computer conducts summary analysis. PLC uses industrial communication optical fiber to communicate with the upper computer to control the operation of each workstation in the production line.

For medicines that require high loading accuracy for the treatment of heart disease, an error of less than 1% is acceptable, while a peristaltic pump driven by a stepping motor is subject to external factors such as the diameter of the silicone tube, the liquid level of the medicine, and air bubbles. interference, the risk of error is high. The filling accuracy of the servo motor-driven volumetric pump is ±1% theoretically, but online spot checks are required to check the filling volume every hour or so during the production process.

The high-speed computing PLC can realize this function with the help of the data transmitted by the pressure module. This will significantly reduce human error and interference. In the A-level purification area (that is, the filling area), enterprises need to focus on monitoring the number of dust particles in the environment. At present, most of them use independent detection instruments for detection and alarm. The high-performance PLC integrates the above data for centralized control. It can reduce a large number of on-the-job personnel, which can also reduce the quality risk of medicines.

At present, there are many PLC manufacturers, various versions, different standards, and poor versatility. It makes it difficult to realize a specialized and standardized control system. The future development trend of PLC in the pharmaceutical industry is to use standard communication interfaces, integrate secondary instruments, attach other systems, and use excellent executive components in the electrical industry to monitor, record, and archive data in all links of production to achieve high intelligence. unattended production line. Technicians only need to remotely monitor the data or reports fed back by the PLC to complete production.