Application of wireless communication temperature and humidity sensors in temperature and humidity measurement in the tobacco industry

Note: This solution is also applicable to other areas that require environmental temperature and humidity monitoring, such as finished product warehouses, alcoholization warehouses, fermentation warehouses, and tobacco storage rooms. Now we only take a tobacco fermentation warehouse as an example.

1 Overview

The wireless communication temperature and humidity sensor (WOW) is a new generation of high-precision digital sensors from PointSix, USA. Compared with online temperature and humidity sensors, it has the following advantages:

1) There is no restriction on the installation location of the wireless temperature and humidity sensor and no wiring is required. (Within the range of radio communication distance)
2) The wireless temperature and humidity sensor adopts a waterproof design and can be used in very humid environments.
3) The installation and maintenance of the wireless temperature and humidity sensor are very simple.
4) The use of cables is reduced, the system cost is reduced, and the reliability of the system is improved.
5) If the fermentation warehouse is renovated, the wireless temperature and humidity sensor does not have the problem of connecting cables and can be disassembled at will, and there is no problem of repeated investment.
6) The system can be easily connected to the automatic control system of the air conditioner.

For the convenience of introduction, the following is an example of a tobacco factory for the scheme. The fermentation warehouse of the cigarette factory adopts artificial fermentation and consists of 31 fermentation rooms. Each fermentation room can hold 400 to 600 packs of cigarettes, and each fermentation cycle is 15 days. The fermentation task of 10,000 to 30,000 packs must be completed every month to ensure the annual production plan of the cigarette factory.

2 Basic procedures of artificial fermentation

1) Heating stage: The temperature rises from room temperature to 45°C, the relative humidity is 55%-60%, and the time is 3 days.
2) Insulation stage: The temperature is stable at 45°C, the relative humidity is 60%-65%, and the time is 9 days.
3) Cooling stage: The temperature gradually drops to room temperature, and the time is 3 days.

3 User demand analysis

The fermentation warehouse currently has 37 staff members, who adopt a four-shift three-shift operation mode. Every two hours, someone is sent into the fermentation room to copy the indoor ambient temperature, humidity, and cigarette pack core temperature, 365 days a year without interruption. Since the temperature and humidity in the fermentation room are usually maintained at around 45°C and 60%, the room is filled with hot and humid steam and the pungent smell of smoke from the cigarette packs. The working environment is poor, which affects the health of the operators. Moreover, the accuracy and integrity of data cannot be guaranteed by the manual timed data recording method; data processing and production management still remain in the backward manual tabulation mode. Compared with other workshops in the cigarette factory, the production status monitoring and production management level of the fermentation warehouse are indeed backward. The

fermentation warehouse used Apple computers and single-board computers to automatically detect temperature and humidity. Due to signal interference and spare parts problems, the system was abandoned after two years of operation.

4 System design indicators

1) High reliability, can run uninterruptedly all year round.
2) The system is simple to maintain and easy to use.
3) High degree of automation , it is best to be able to automatically control temperature and humidity.
4) It is best to have on-site temperature and humidity display outside each fermentation room.

5 Basic functions of the system

1) Automatically monitor the measured values ​​of all sensors and display them on the computer screen in real time.
2) Curve function: Provide real-time and historical trend graphs, and display the changes of environmental temperature, humidity and core temperature on the screen with curves.
3) Report function: Output reports according to user requirements, print recorded data and curves of temperature and humidity changes.
4) Sensor parameter modification function: Modify and set the parameters of sensors on the Internet through the communication network (station address, range, zero point, temperature coefficient)
5) Scheduling and management function: The system has the function of providing WWW services for production plan issuance and production status through the Internet network on the existing hardware platform

6 System solution

6.1 Data acquisition solution

According to the requirements of temperature and humidity control in tobacco fermentation warehouse, the new generation of wireless digital environmental temperature and humidity monitor WOW and the new generation of offline temperature and humidity recorder ILogger-THT are planned to be used for temperature and humidity control and monitoring of tobacco fermentation warehouse. WOW is used in conjunction with the HA8-WOW device developed by PointSix to realize 24-hour real-time automatic monitoring of temperature and humidity at multiple points in the tobacco fermentation warehouse. The offline temperature and humidity recorder ILogger-THT can monitor and record the temperature and humidity of products that need to be focused on temperature and humidity control in the tobacco fermentation warehouse for 24 hours in real time. The specific plan is as follows:

According to the internal structure and layout characteristics of the tobacco fermentation warehouse, 3 to 4 WOW temperature and humidity monitoring points are set in the fermentation warehouse. These monitoring points will be optimized according to the actual situation. The principle of optimizing the setting of monitoring points is:

1) The monitoring points should be set in the fermentation warehouse away from the air outlet of the ventilator and air conditioner or the location with poor ventilation effect;
2) The monitoring points are distributed as evenly as possible in the fermentation warehouse to ensure effective monitoring of the temperature and humidity of the entire fermentation warehouse;
3) The monitoring points should be reasonably arranged according to the actual situation of temperature and humidity in the fermentation warehouse. For example, the temperature near the ceiling and on the ceiling of the fermentation warehouse is generally higher than other locations in the warehouse, and a certain number of monitoring points should be considered. The humidity is high on the wall close to the ground, and there should also be a certain number of monitoring points;
4) The location of the monitoring points is based on the principle of not affecting the stacking and transportation of tobacco packages in the fermentation warehouse.

The temperature and humidity information monitored by each WOW is received by the HA8-WOW receiver. This information is connected to the central control computer by the HA8-WOW through the 1-Wire™ network. The central control computer interprets and analyzes all monitoring data and forms a historical trend chart of temperature and humidity monitoring at each monitoring point. If the temperature and humidity of one or several temperature and humidity monitoring points are found to be abnormal, the central control computer will determine the location of the abnormal monitoring point and determine which ventilator or air conditioner is abnormal through optimization calculation. The principle of optimization calculation is:

1) Ensure that the temperature and humidity abnormalities are controlled in the shortest time;
2) Select the ventilator or air conditioner that is closest to the temperature and humidity abnormality. [page]

While monitoring the temperature and humidity at fixed monitoring points in the fermentation warehouse, some monitoring points that need to be monitored can also be monitored. The specific measure is to use the offline temperature and humidity recorder ILogger-THT. Install the offline temperature and humidity recorder ILogger-THT at the location that needs to be monitored. ILogger-THT will measure the temperature and humidity at pre-set time intervals and record them on the Ibutton information button of ILogger-THT. The management personnel can regularly download the temperature and humidity measurement results recorded on the Ibutton information button of ILogger-THT to the central control computer. The central control computer will organize the downloaded data and form an analysis report and a temperature and humidity historical trend chart of the monitoring point. For each fermentation warehouse, it is generally considered to configure 1 to 2 offline temperature and humidity recorders ILogger-THT.

Regarding the control of the ventilator and air conditioner in the fermentation warehouse, if the automatic control system of the ventilator and air conditioner in the fermentation warehouse has been established, then it is only necessary to transmit the control signal of the central control computer to the system. If the automatic control system of the ventilator and air conditioner in the fermentation warehouse has not been established, a PLC controller can be used to realize the automatic control of the ventilator and air conditioner by the central control computer. How to implement this part of the control depends on the specific situation of the fermentation warehouse, and this article will not discuss it in detail.

6.2 System composition

The fermentation warehouse temperature and humidity control system consists of five parts: central control computer, high-precision digital environmental temperature and humidity sensor based on wireless communication - WOW, HA8-WOW host adapter, wireless communication network, offline temperature and humidity recorder ILogger-THT, etc.

6.3 Performance parameters

6.3.1 WOW wireless temperature sensor

WOW wireless temperature sensor is a battery-driven digital temperature sensor with a built-in microprocessor and a wireless frequency of 418 MHz. It is an FCC-certified wireless transmitter.

1) Main features:

• Information button DS18B20 with 64-bit ID and digital temperature sensor
• Direct digital sensor technology
• Up to 45 meters away from HA8-WOW receiver
• Transmission rate can be set from 10 to 255 seconds
• 100 sensors can work simultaneously
• Battery can work for 2 to 5 years
• Small size, ABS shell (4×5×1 cm)
• Waterproof, suitable for humid environment
• ID and temperature transmission with CRC16 check
• Built-in loop antenna

2) Performance parameters:

• Transmission rate 10-255 seconds can be set
• Storage time in static mode after installing batteries can be stored for 5 years (using backup battery can work for 10 years)
• Dimensions (outline) 4W X5 H X1 D (cm)
• Mass 30 grams
• Storage temperature -30 to 85 degrees Celsius
• Operating temperature -30 to 85 degrees Celsius (backup battery -30 to 85 degrees Celsius)
• • Battery life (CR2032) in transmission mode 2-5 years with CR2032 and transmission cycle of 10 to 240 seconds
• Battery life in transmission mode (backup battery) 3-7 years with backup battery and transmission cycle of 10 to 240 seconds
• Battery CR2032 three-volt lithium battery or 3.6-volt lithium battery
• FCC certification FCC ID: M5ZWOW

6.3.2 HA8-WOW

HA8-WOW is an ASCII code RS232 or RS485 to 1-Wire network host adapter with built-in wireless frequency 418MHz receiver. HA8-WOW is an RS232 or RS485 to 1-Wire network interface. The interface provides an ASCII code command set for a built-in controller and DOS-based application to match iButton 1-Wire network devices and wireless sensors.

Main Features:

• Supports ASCII code instructions for 1-Wire network
• Built-in 418MHz wireless receiver
• Receives, decodes and verifies each wireless packet from wireless sensors
• Automatically provides a smart plug-in interface for wired products
• Each 1-Wire-based CAT-5 network can connect to 600 meters and 100 devices
• Each host serial port supports 26 host adapters
• Baud rate from 600 to 115K selectable
• Adapter address from 1 to 26 selectable
• With RJ-11 connector and RS232/RS485 interface cable
• 3 identical RF11s provide a simple network interface
• Provides search, conditional search and full search instructions
• Supports Touch Memory file format
• Automatically generates TMEX and CRC16 check
• Module mode instructions support all 1-Wire network functions
• • More than 27 kV ESD protection (IEC801-reference mode.)

6.3.3 Offline temperature and humidity recorder ILogger-THT

Offline temperature and humidity recorder ILogger-THT includes: ILogger-THT tester, time calibration information button DS1994, temperature and humidity recording information button DS1996. The

main functions and features of the ILogger-THT tester are:

• Relative humidity and temperature measurement
• Relative humidity and temperature can be calibrated by NIST
• Each ILogger-THT has a unique 64-bit electronic serial number, and each temperature and humidity record is marked with time and date for easy computer management and data classification records
• Built-in replaceable lithium battery, which can be used continuously for 2 years
• LED operation indicator is used for easy use and operation
• Can be wall-mounted or surface-mounted for easy installation [page]

The main performance parameters of ILogger-THT are as follows:

6.3.4 Monitoring computer

• The host uses a standard "Pentium" industrial control computer
• PENTIUM III 500
• 128M RAM; 20G hard disk
• 20'CRT;
• Printer,
• Multimedia kit; Communication interface6.3.5

Software configuration

• Chinese WINDOWS NT 4.0 SP5
• INTOUCH 7.1 industrial configuration software, DDE communication protocol
• MICROSOFT EXCEL spreadsheet software6.3

. 6 Environmental parameters

• Temperature: +10℃～+30℃
• Humidity: < 85% (25℃)
• AC voltage: 380V AC
• Ground wire: Signal ground ground resistance < 4 ohms6.3.7

Upper computer software performance

The third generation object-oriented industrial configuration software with the largest market share in the world is selected - INTOUCH industrial configuration software of WONDERWARE. In actual use, we believe that this software has the following advantages:

• Chinese WINDOWS platform, which completely solves the problem of Chinese localization.
• It is in line with the development trend of computer systems.
• Software development is intuitive and easy to understand, which is convenient for users to conduct secondary development and system integration.
• It uses standard data format and shares data with MICROSOFT's EXCEL spreadsheet software, so users can easily develop their own management software.

7 Construction period

1) Feasibility report preparation and review: 1 month
2) Purchase and debug components and system hardware: 3 months
3) Software design, installation, and debugging: 1 month
4) On-site installation and system debugging: 2 months
5) Software design and component purchase can be carried out in parallel, and the total construction period is 6 months.

8 Feasibility and benefit analysis of the scheme

The fermentation warehouse temperature and humidity automatic control system scheme is a project improved on the basis of the current military product finished product warehouse technical scheme. The feasibility analysis is as follows:

1) The temperature and humidity control system adopts the wireless high-precision temperature and humidity monitor WOW and the offline temperature and humidity recorder ILogger-THT of PointSix Company of the United States. The monitor has the characteristics of high measurement accuracy, good measurement accuracy stability, high measurement reliability, and can perform 24-hour uninterrupted measurement, which meets the requirements of fermentation warehouse temperature and humidity control. In addition, the above-mentioned measuring instruments have been successfully used for temperature and humidity control in grain depots, oil depots and other projects, and are mature technologies;

2) The high-precision digital environmental temperature and humidity sensors using wireless communication methods can achieve more significant economic benefits.

The benefit analysis of the use of this temperature and humidity automatic control system is as follows:

1) The fermentation warehouse temperature and humidity automatic control system will realize the automation of fermentation warehouse temperature and humidity monitoring, which is of great significance to improving the reliability of fermentation warehouse temperature and humidity monitoring and realizing the scientific management of fermentation warehouses. Especially for cigarette factories, quality control is its lifeline, and the temperature and humidity automatic control system will be an important guarantee to ensure the quality of fermentation.

2) With a relatively small investment in funds, the fermentation warehouse can realize the automation of temperature and humidity monitoring through certain technical improvements, which can raise its management level to a new level;

3) The automatic control system has good scalability. After the central computer is established, the unified monitoring and management of multiple fermentation warehouses can be realized through computer networks or telephone lines in the future, which truly achieves "one investment, long-term benefits".

In short, the completion of the fermentation warehouse temperature and humidity automatic control system will play a certain role in promoting the modernization of fermentation warehouse management and has good economic benefits.

Performance and price comparison between wireless temperature and humidity sensors and ordinary temperature and humidity sensors: