[Abstract] This article mainly introduces the functions and effects that Delta Automation products need to achieve when used on drying and granulation (pharmaceutical) equipment. From the perspective of existing equipment requirements, Delta Automation products can fully meet the functional needs of these types of pharmaceutical equipment.
【Abstract】This paper mainly introduces theDeltaautomationproductsofdryinggranulatingneededtousefunctionandcanachievetheresult.Fromtheexistingequipmentrequirements,setsofautomationproductscancompletelymeetthefunctiondemandofthesetypesofpharmaceuticalequipment.
[Keywords] Drying; Granulation; Heating; Frequency converter; Touch screen; PLC
1. Basic Principles of Drying and Granulation (Pharmaceutical) Equipment
The material is manually added to the container, and then the PLC-controlled solenoid valve seals the container. A blower is started to pump air into the container (i.e., air intake), which needs to be heated and filtered. The air intake blows the material into a boiling state. After the material boils, a slurry is sprayed onto it using a spray gun (i.e., spraying). After spraying, air intake continues to dry the material.
2 Control System Requirements
(1) Control the solenoid valve to operate according to logic;
(2) Control the heater to precisely control the inlet air temperature;
(3) Collect, save, and print sensor signals;
(4) Store setting parameters;
(5) Control the frequency of the blower and the frequency of the liquid spraying motor.
The control system scheme is shown in Figure 1.
Figure 1 Control System Scheme
The touchscreen, PLC, and frequency converter all use Delta products. Analog modules mainly use 04AD and 04DA modules, while temperature modules mainly use 04PT, 04TC, and DTC1000. Printers are optional, primarily using EPSON ME2 or Weihuang Micro Printer.
3 solutions
The PLC controls the solenoid valves to operate according to logic. This is a basic function of the PLC, and both Delta ES2 and EHPLC can meet the requirements with reliable control. The PLC output points control relays, which in turn control the solenoid valves. This solves the problem of PLC output point damage caused by wiring errors, and also makes it easier for customers to diagnose and resolve faults when equipment malfunctions. For example, if a solenoid valve does not operate, simply check if the corresponding relay indicator light is on and if its contacts are connected. If the relay is normal, the problem lies with the solenoid valve. Once the conclusion is reached, the user can replace it themselves, avoiding the need for the equipment manufacturer to send personnel to resolve the issue, thus saving costs. Using a Delta touchscreen, the system can guide the operator through the steps and prevent certain operations from being performed if conditions are not met, ensuring the operator's personal and property safety. The operation process can be displayed in animation form, making it easier for customers to understand the equipment's principles and observe its operating status. Alarm functions facilitate customer maintenance.
The heater is controlled to precisely regulate the inlet air temperature. Generally, the inlet air temperature should be controlled within ±0.5℃. There are generally two heating methods: electric heating and steam heating. Both types of heaters work by controlling the heater temperature, thereby affecting the heat exchange between the heater and the air to control the inlet air temperature. Electric heating uses either a solid-state relay or a silicon controlled rectifier (SCR) phase-shift trigger, depending on the heating power. Steam heating uses a proportional valve to control the amount of steam entering the heater, thus controlling the heater temperature.
Solid-state relay heating (electric heating) is mainly used in small equipment, such as pharmaceutical manufacturers for process testing. Higher temperature control accuracy is better. In this case, we generally use the Delta DTC1000V temperature control module. This module provides accurate temperature measurement and can connect to various types of sensors, such as RTDs and thermocouples. Its 12V output pulse can directly control the solid-state relay, simplifying the circuit. The PLC reads the module's measured values via RS485, writes the target temperature control value, and activates the module's self-tuning function (AT) as needed. After using this module, only one self-tuning is needed during trial operation; excellent control can be achieved without manually modifying the PID parameters, and the actual temperature can be controlled within ±0.1℃ of the set temperature.
Thyristor phase-shift triggering (electric heating) and steam heating are generally used in large-scale equipment, which is mass-produced. Both require analog signals of 0-10V or 4-20mA for control. In this case, we typically use Delta 04PT or 04TC modules to measure temperature, combined with the PLC's fuzzy temperature control function (FTC instruction), and use the 04DA module to output analog signals for heating control. The FTC instruction mainly has two parameters: control cycle and heating environment selection. These two parameters are listed on the touch screen for users to change, as shown in Figure 2. Users can select appropriate control cycles and heating environments according to different heater power to keep the actual temperature within ±0.3℃ of the set temperature.
Figure 2 shows the current FTC instruction output value in a bar chart, which is convenient for technicians to debug.
The system collects, saves, and prints sensor signals. During production, it's necessary to collect signals such as airflow and negative pressure within containers. These signals are converted into 4-20mA analog signals by sensors and output to the 04AD module. The PLC reads the converted values from the 04AD module, calculates them, and displays them on the touchscreen. Using the touchscreen's history buffer function, these signals can be stored on the touchscreen periodically. The amount of data stored varies slightly depending on the touchscreen model. For larger data storage, a USB flash drive can be inserted to store the data. After data is stored on the touchscreen, it can be used to create historical trend charts or displayed as historical value tables. The data can be copied to a USB flash drive (CSV format) and then edited on a computer. All of this can be accomplished with just a component on the touchscreen, making it very convenient. The system can also use the GETHISTORY macro instruction in conjunction with the touchscreen's printing function to print the data, as shown in Figure 3.
Figure 3 shows the start and end times and data for each print record after the user selects them, along with the current parameter values (SETPARAMETERS section). Pressing the "Print" button begins printing. The print format can be customized, including adding your company logo, necessary notifications, etc.
Regarding storing setting parameters, the recipe function on the touchscreen can be used conveniently. Simply changing the value of RCPNO allows selection of the corresponding recipe, and the BMOV macro instruction can be used to transfer the recipe to the PLC or vice versa.
For controlling the frequency of the blower and the liquid spraying motor, the blower uses Delta's VFD-F series frequency converters, while the liquid spraying motor generally uses VFD-M series frequency converters. Delta frequency converters all have RS485 communication ports, allowing for easy connection to a PLC. The PLC communicates with the frequency converter using MODWR and MODRD instructions, enabling adjustments to the frequency converter's operation, display of its status, and control of its start/stop on a touchscreen, without requiring additional components. The reliability of Delta frequency converters significantly reduces after-sales service costs for equipment manufacturers.
4. Summary
Delta's touch screens, PLCs, and frequency converters can meet the control requirements of this type of equipment in drying and granulation (pharmaceutical) equipment. They are simple to use, highly integrated, easy to operate, have a low failure rate, and save costs.
With factories becoming increasingly automated, there's a growing need to centralize the monitoring and control of various devices. This places higher demands on equipment manufacturers, requiring their equipment to integrate with existing factory control systems. Delta offers solutions for this purpose: serial MODBUS, Ethernet MODBUS, and CANOPEN bus solutions. Many manufacturers are already using serial MODBUS to connect Delta touchscreens to their host computer monitoring systems. Delta's solutions will help more equipment manufacturers easily integrate their devices into centralized control systems.
