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On-Line Detection And Control Analysis Of Purified Water System In Pharmaceutical Engineering

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The pharmaceutical water system has certain complexity. In the process of production, storage and transportation, if the purified water is polluted, it will seriously affect the quality of the medicine. Therefore, it is necessary to build a purified water detection system to ensure that the pharmaceutical water meets the standards. In the context of the rapid development of PLC technology, an online automatic detection system for purified water in pharmaceutical engineering is constructed to monitor the quality of pharmaceutical water in real time to ensure the quality of pharmaceuticals.

 

Part 1 Introduction

 

A large amount of purified water is needed in the pharmaceutical production process. The tap water is filtered by mechanical filters and activated carbon filters, and then the water source is purified by intermediate water tanks, mixed beds of yin and yang resins, and ultraviolet disinfection. In this process, it is necessary to pay close attention to the pH value, conductivity, total organic carbon and other indicators of the purified water. Using the traditional offline detection mode not only has a high detection cost, but also has a certain hysteresis. In order to improve the detection efficiency of purified water, a set of online automatic detection equipment is designed by using PLC technology to realize remote monitoring of the quality of purified water in pharmaceutical engineering.

 

Part 2 Continuous Production Process Control of Pharmaceutical Water

 

The control of pharmaceutical water is an important basis for ensuring the quality of pharmaceuticals. In order to meet the production needs of pharmaceutical production lines, pharmaceutical water adopts a continuous production mode, and the water system operates continuously.

 

2.1 Establish A Continuous Production Process Control Model

 

On the whole, the control of the continuous production process is mainly divided into two aspects, namely, the production management level and the real-time control level. The former mainly includes production plans and production scheduling plans formulated by pharmaceutical companies, while the latter mainly includes drug production management, safety management, supply management, etc. Based on the above two aspects, a continuous production process control model is constructed.

 

2.2 Define The Control Objectives Of The Pharmaceutical Water System

 

In the process of producing pharmaceuticals, the control objectives of the water system mainly include 8 items:

 

  • The control of the water system should be accurate, flexible and fast;

 

  • Real-time monitoring of the operation of the pharmaceutical water system through the remote control mode;

 

③Optimize the control method, improve the operation efficiency of water-making equipment, and ensure that the quality of pharmaceutical water meets the requirements of pharmaceutical production;

 

  • Key parameters such as conductivity and TQC of pharmaceutical water should be monitored to ensure that they meet the requirements of relevant parameters in the Pharmacopoeia, so as to avoid contamination of pharmaceutical water and affect the quality of pharmaceuticals due to important parameters that do not meet the requirements;

 

  • Use remote control technology to regularly maintain and maintain the equipment, parts and sensing devices in the pharmaceutical water system;

 

⑥Remote control of parameters of pharmaceutical water equipment is realized by using PLC and signal transmitter;

 

⑦ Equip the pharmaceutical water system with an online early warning system and a fault repair system to ensure that when the system fails, relevant maintenance personnel can deal with it as soon as possible to reduce the scope of the pharmaceutical water system failure;

 

⑧A storage module is embedded in the pharmaceutical water line control system to automatically store important parameters for relevant staff to consult and retrieve at any time.

 

Part 3 Pharmaceutical Water Automatic Control System Adapts To Each Production Link

 

The preparation process of each drug is different, and the selection of equipment is also very different. Take the pharmaceutical water system of a pharmaceutical company as an example. The company installed the pharmaceutical water system in a general area and equipped the system with a separate water making room to ensure that each water point is in a clean area.

 

3.1 Raw Water

 

The raw water link is mainly composed of a water pump, a water inlet valve and a water storage tank. Its main function is to pretreat tap water and provide a continuous water source for the purified water system. Designing an automatic control system in this link can ensure that the raw water inlet valve and the liquid level of the water storage tank form an interlocking state, and realize the automatic regulation of the liquid level of the raw water storage tank.

 

3.2 Pretreatment System

 

The pretreatment system is mainly composed of softener, impurity filter and other equipment. The pretreatment of raw water is actually to filter the water source provided by the municipal water supply department through physical means (membrane purification system), in this way to reduce the turbidity and hardness of the raw water, and to remove the pollutants in it. Filtration, adjust the pH value of the raw water, and reduce the chloride content of the raw water. Through the pretreatment process, ensure that the source water meets the water demand of the membrane purification system, and improve the working efficiency and service life of the RO membrane enhancement system.

 

3.3 Purification Equipment

 

The purification filter is mainly composed of EDI (system water treatment equipment) detection device and RO membrane. It is equipped with an automatic detection system for this link. online test. In the storage system, the online detection function is mainly used to monitor the real-time parameters of the temperature sensing device, water inlet valve and liquid level sensing device. At the same time, the status detection of the valves at the connection between the water storage tank and each water point is carried out.

 

Part 4 Software Design Of Online Detection Control System

 

4.1 Control System Software Design

 

In this design, the staff used the programming/configuration language modules uniformly provided by the supplier, including modules such as functional diagram language, ladder diagram language, and structured language. Programming computer language modules. When actually carrying out software design work, relevant staff should flexibly choose an appropriate programming language according to the operation of the water system and the actual needs of online testing.

 

It should be noted that when selecting programming software, not only the adaptation of the software to the controller of the pharmaceutical water online detection system must be considered, but also the requirements for the quality of pharmaceuticals in GMP (Good Manufacturing Practice). Therefore, the staff chooses relatively mature programming software with certain technical accumulation, and uses mature programming software to ensure that data can be read and recorded between different software versions, and realize code traceability and module testing functions.

 

4.2 Selection Of Upper Computer

 

In the process of constructing a control system with a PLC single-chip microcomputer, there are high requirements for the functions of the upper computer. In order to ensure that the software system of the upper computer is compatible with the hardware system, the researchers chose the configuration software provided by the upper computer manufacturer, that is, SIMENS Win CC software. And the control system chooses SI-EMENS-S7300 single-chip microcomputer. In the process of deploying the upper computer software system, the staff should check the integrity of the software and verify whether it supports the key software of the online detection of the pharmaceutical water system, such as batch control (BATCH), management information interface, etc. [3]. In addition, the host computer software system must also support GMP’s requirements for data records and electronic signatures, so that the host computer software can have good scalability in future work.

 

4.3 Software Function Design

 

Since the pharmaceutical water system is in an uninterrupted working mode, the real-time continuous control capability of the software should be considered when designing software functions, mainly including: production management capabilities, process chain control, safety management, pharmaceutical water process I/O, parameter detection, Functions such as early warning and alarm and data recording ensure that the system can conduct remote online supervision of the complete pharmaceutical water process.

 

4.4 Software Structure Design

 

This design follows the principle of software design structure, and divides the software into three levels: the top level is the control level of the pharmaceutical water system, which is responsible for testing and monitoring all aspects of the pharmaceutical water system and various equipment; the middle layer is the pharmaceutical water production line. Each equipment unit, such as liquid storage tank, valve, water pump, filter, etc.; the bottom layer is the display instrument corresponding to each equipment, or the operation unit corresponding to the equipment.

 

4.5 Hardware Design

 

In terms of hardware design, this design uses SIEMENS S7300 single-chip microcomputer, which is widely used in the pharmaceutical industry and has outstanding performance in terms of work stability and work efficiency.

 

4.5.1 Digital Input Unit

 

The main function of the digital input unit is to transmit the digital signal to the PLC microcontroller to form a connection between the microcontroller and the input digital signal. For example, the start/close status of the water point, the working status of the frequency conversion device, etc. The staff is equipped with a two-wire proximity switch module and a standard switch module for signal connection in the unit, and uses a monochrome LED screen to display the input of operation instructions. The advantage of this design mode is that there is no strict restriction on the use of slots. Modules In terms of plugging and unplugging, the staff can input the address according to the signal and allocate the slots reasonably.

 

4.5.2 Digital Output Unit

 

The main function of the unit is to convert the process variable generated by the control device into a digital signal and transmit the digital signal to other unit modules. In actual work, when the PLC microcontroller generates a control command, its internal signal level is converted into an external signal level that can be recognized by each module and the operation terminal. In this way, the control of the water pump and valve is realized to ensure that the control signal can be used in the between different modules. In this design, when selecting the output unit, the 6ES7322-1BH01-0AA0 digital output unit is used. This device has 16 signal output channels. It not only has a compact design, but also uses the front connector slot to lock the output IP.

 

4.5.3 Analog Input Unit

 

Using the analog input unit, the microcontroller can be connected to the analog process signal to ensure that the PLC microcontroller can receive data such as flow, conductance, temperature, pressure, etc., and realize the online detection of various aspects of pharmaceutical water. Working mechanism: After the analog input unit receives the analog signal, it converts it into a digital signal that can be read, recorded, and saved by the PLC. The format is 13 digits + sign bit, and the signal reception and conversion can be recorded correctly through this mode. , the sending time. In actual work, the analog measurement range can be flexibly adjusted according to different detection requirements, and basic measurement ranges such as current and voltage can be regulated. At the same time, the parameters can be fine-tuned with the STEP7 configuration module installed in the PG unit. In addition, the unit can also transmit the overrun interrupt sending signal to the programmable CPU to ensure that the analog input unit can send a fault diagnosis report to the CPU in the event of a fault in the production process of pharmaceutical water.

 

4.5.4 Analog Output Unit

 

The function of the quantity output unit is to convert the digital signal generated by the PLC into an analog signal and transmit it to each control unit. Usually, this unit is connected with the analog quantity execution unit and the frequency conversion control unit. The analog output unit used in this design has 15-bit resolution, which ensures that various current and voltage measurement ranges can be individually set through parameter assignment software. When the pharmaceutical water system fails, the fault report can be sent to the programmable In the controller, it is convenient for operation and maintenance personnel to troubleshoot.

 

4.5.5 Instruments And Valves

 

Some instruments and valves in the pharmaceutical water system are in direct contact with medicines. In order to avoid deterioration of medicines, designers need to strictly control their temperature resistance when selecting instruments and valves. At the same time, optimize the layout of instruments and valves to avoid dead end.

 

Part 5 Conclusion

 

Pharmaceutical work requires a large amount of purified water. In order to avoid drug contamination, the quality of purified water needs to be tested in real time. The traditional offline detection method of purified water is inefficient and cannot effectively control the cost. In order to solve this problem, relevant researchers of a pharmaceutical company tried to use PLC technology to establish an online detection system for pharmaceutical engineering purified water, using SI-EMENS-S7300 PLC single-chip microcomputer as the processor of the detection system, equipped with a 3-layer system framework, Realize effective connections to digital input/output units, analog input/output units, and instrument valves to ensure that the quality of purified water always meets pharmaceutical needs.

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