CHEMICAL ENGINEERING TRANSACTIONS  
 

VOL. 51, 2016 

A publication of 

 
The Italian Association 

of Chemical Engineering 
Online at www.aidic.it/cet 

Guest Editors: Tichun Wang, Hongyang Zhang, Lei Tian 
Copyright © 2016, AIDIC Servizi S.r.l., 

ISBN 978-88-95608-43-3; ISSN 2283-9216 

Study on a Measurement and Control System for Greenhouse  
Fang Cheng*a, Shuangyou Wangb 
a College of Information Science and Technology ,Agricultural University of Hebei,Baoding 071000,China 
b Software School, Handan College, Handan, Hebei, 056001, China 
1041169389@qq.com 

We develop a distributed and multi-span measurement and control system for greenhouse based on CAN bus 
using communication technology and embedded technology. The information of environmental factors 
(temperature, moisture, illumination) is collected, processed, transmitted and controlled. This paper presents 
the design flow charts of hardware circuits and software. Experiment shows that the measurement and control 
system for greenhouse can meet the goal of environmental monitoring and is worthy of popularization.  

1. Introduction  

The major part of China belongs to continental monsoon climate and the winter and summer monsoon winds 
blow in opposite direction. The winter is cold and dry, while the summer is hot and raining. The four seasons 
are distinct, which is unfavourable for crop group. Moreover, north and south China have very different climate. 
Due to low temperature, many months are not suitable for agricultural production in North China. Technologies 
are indispensable for developing modern agriculture.  
At present facility agriculture plays an important role in China and the popularization of facility agriculture can 
promote modernization of agriculture, while increasing agricultural yield and peasants’ income (Chen, 2014). 
Greenhouse is a crucial part of facility agriculture. To meet people’s need and to keep pace with the trend of 

agricultural technology, artificial intelligence has been introduced into greenhouse. This new technology 
enjoys a huge development potential.  
The greenhouses referred in this study are conventional greenhouses in China as well as the intelligent 
greenhouses from foreign countries. The measurement and control system for greenhouse proposed 
integrates sensor, intelligent control, single-chip microcomputer and communication technologies.  

2. Overall design 

2.1 Working principle  

The measurement and control system for greenhouse consists of 3 parts: sensors, controller and 
environmental control system. Sensors are used for collecting parameters of the greenhouse environment and 
converting them into digital signals as input into the microcontroller. Environmental control system is used for 
controlling the parameters of the greenhouse environment. The controller presents the logic of the entire 
control mechanism with the flexible programming of the interaction between the input of sensor data and 
output of environmental control system.  
Therefore, the control based on different rules is achieved. Below is the closed-loop circuit of the control 
system (Fig. 1).  
 
 
 

                               
 
 

 

 
   

                                                  
DOI: 10.3303/CET1651110

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Please cite this article as: Cheng F., Wang S.Y., 2016, Study on a measurement and control system for greenhouse, Chemical Engineering 
Transactions, 51, 655-660  DOI:10.3303/CET1651110   

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Greenhouse 

Controller

Greenhouse 

Environment 

Control 

Equipment

Greenhouse 

of crops

Environmental 

parameters 

collection

 

Figure 1: Working principle of the system  

2.2 Hardware design  
The block diagram of hardware design is shown in Fig. 2. The hardware mainly includes sensor circuit, 
microcontroller, input/output (I/O) module, power supply processing module, CAN bus interface and USB 
interface. Data collection module is responsible for collecting parameters of the greenhouse environment 
using sensors and front-end data processing. The sensors used are divided into two types: sensors with 
analogue output or digital output. The analogue signals are directly transmitted to the controller via a built-in 
A/D converter of the chip. The controller processes the data, makes judgment following the preset control logic, 
and finally outputs the control signals with the opening or closure of corresponding output equipments. I/O 
module consists of relays, photoelectric isolation and greenhouse equipments(Guo et al., 2013). The power 
supply module provides SV and 3.3V power supply. Human-machine interaction module realizes menu 
operation and parameter configuration. CAN interface and USB interface provide connections between a 
single greenhouse and the upper computer for multi-span, integrated management.  

Real Time Clock

Alarm circuit

Display circuit

data storage

Monomer Greenhouse  

(sub-station)

CAN to USB

PC

USB bus

CAN bus

H
u
m

id
ity

 S
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n

s
o

r

T
e
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p
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e
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L
ig

h
t s

e
n

s
o

r

R
e
la

y
 c

o
n

tr
o

l

Monomer Greenhouse  

(sub-station)

 

Figure 2: Block diagram of hardware design  

2.3 Software design  
Software design includes the design of control system software for a single greenhouse, CAN bus 
transmission, USB data transmission and upper computer management software. Control system software for 
a single greenhouse has the following modules: system configuration, alarming configuration, stage control, 

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http://cn.bing.com/dict/search?q=isolation&FORM=BDVSP6&mkt=zh-cn


historical data, expert database and growth stage logic control. By choosing the operating mode, configuring 
expert database, dividing the control stages and connecting with equipments, a flexible programming is 
possible between the control logic and executing devices. Therefore, logic control is realized for the 
equipments at each growth stage and then for the entire crop growth process (Tan, 2015). The software for 
upper computer management is written using C# programming language, an object-oriented 
programming language, to enhance auxiliary management function of the greenhouse control system. CAN 
bus protocol is responsible for data transmission between the greenhouses and for multi-span management 
by the upper computer via the USB communication protocol. The design of the software for single greenhouse 
control system is shown in Fig. 3  
 

System Settings
Alarm Settings

Stage Setting 

Historical dataExpert Database

The 

main function

 

Figure 3: Function block diagram of single greenhouse control software  

3. Hardware design  

3.1 S3C6410 controller 
S3C6410 controller is a 16/32-bit RSIC microprocessor developed by Samsung based on ARM11 processor 
core. This controller is featured by high price performance, low power consumption and ease of development 
and the ability to enhance the peripherals. S3C6410 controller is used in the single greenhouse control system. 
Its high-capacity memory and diversity of peripheral interfaces make it easier for functional update and for 
meeting the control requirement.  

3.2 Sensor interface design 

3.2.1 DS18B20 and single-chip microcomputer interface design  

There are two types of interface circuit connections for DS18B20 and single-chip microcomputer. One is 
connection of power supply to VDD, with grounding of GND and connection of I/O interface of single-chip 
microcomputer to DQ pins. The other is the use of parasite power for power supply, with grounding of VDD 
and GND and connection of DQ pins to I/O interface of single-chip microcomputer. Regardless of the mode of 
connection, when the DS18B20 sensor is writing memory and performs A/D conversion of the temperature 
data (Hu and Liang, 2014). The temperature sensor circuit is shown in Fig. 4.  
 

 

Figure 4: Temperature sensor circuit for DS18B20 

3.2.2 Design of air moisture sensor circuit  
HIH-4000 Series Humidity Sensors (Honeywell) are used.HIH-4000 Series Humidity Sensors have high output 
voltage and linearity. Therefore, no external conditioning circuits for signal amplification and non-linear 
correction are designed. The sensors are already capable of processing weak signals. VDD is connected to 
the 5V power supply, with GND grounded and OUT as the output terminal that outputs 0.8V-3.9V analog 

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voltage signals. The corresponding relative humidity is 0% RH-100% RH. In our design(Yin and Zhao, 2014), 
OUT terminal is directly connected to the PC 4-pin convert on the single-chip microcomputer for A/D 
conversion. The air humidity sensor circuit is shown in Fig. 5.  
 

 

Figure 5: Air humidity sensor circuit 

3.2.3 Design of light intensity sensor circuit  
BH1750FVI light intensity sensor is connected to I2C bus. When the 12C bus is idle, SDA and SCL are at high 
electrical level. When SCL is at high electrical level, a falling edge of SDA can be used to initialize a start 
condition, while a rising edge of SDA can be used to initialize a stop condition. As shown in Fig. 6, both start 
and stop conditions are issued by the master device. After the start condition ends, the first byte is a 7-bit 
address value, according to which the slave device is chosen. The 8th bit determines the type of operation: 
reading or writing data.  
 

 

Figure 6: Sequence diagram of I2C 

4. Software design  

4.1 Software for single greenhouse control system  

The block diagram of the master program is shown in Fig.7. After power-up, the operating mode and the 
relevant equipments are initialized. All equipments are shut down by the relay of the output control circuit, and 
the master program is run. Master program is the core of software design and crucial for the whole software 
architecture. After the subprogram is started, the following functions are implemented successively: service 
program, modification of the environmental parameter configurations, processing program, data monitoring, 
crystal liquid display and CAN bus communication.  

4.2 Software design for DS18B20 temperature sensor  
The uniline communication of DS18B20 temperature sensor is realized in a time-sharing manner and the time 
interval is strictly controlled. That means the writing and reading of time sequences are very important. All 
operations in DS18B20 temperature sensor should obey this protocol. The communication protocol is as 
follows: initialize the sensor (emit reset pulses), deliver the instruction of memory operation, process the data. 

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start

System 

initialization

Parameter initialization 

of Growth stage 

Read value of 

temperature humidity 

and light

Lcd show

Wait can data?

Wait button？

Growth phase update

Enter menu 

function

Processing 

data

Processing 

data

Y

 

Figure 7: Block diagram of the master program  

4.3 Software design for BH1750FVI light intensity sensor  
The high-precision mode (llx) is chosen for the BH1750FVI light intensity sensor. According to the instructions 
of data manual, an instruction demanding high-precision mode is first sent. After waiting for 180ms, the results 
of light intensity measurements are read from the sensor. The flow chart of receive program is shown in Fig. 8.  
 

start

Wait bus

Send device address, set 

bit zeroth, enter read mode

Waiting for  

reply from the 

machine?

Accept high byte 

data

Waiting for  

reply from the 

machine?

Accept low byte 

data

Send non 

response signal

End

Send stop signal

Set error 

flag

Y

N

Y

N

 

Figure 8: Flow chart of software design for light intensity collection  

5. System testing  

After debugging, the measurement and control system was installed to the greenhouse. All modules operated 
well with good software/hardware coordination. Some parameters were measured using the proposed system 

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for a whole day, with the results shown in Table 1. Since no light was supplemented in the greenhouse during 
experiment, the light intensity control data are not provided.  

Table 1: Parameter measurements of the greenhouse  

Time of 
test 

Temperature 
indoor (°C) 

Humidity indoor (%) Outdoor temperature (°C) 
Outdoor 

humidity (%) 
00:25 17.4 75 17.5 62 
01:12 17.7 75 17.1 62 
03:01 17.6 73 16.1 63 
05:08 16.8 74 15.1 69 
07:41 16.6 73 15.8 78 
09:26 18.7 75 17.1 62 
11:28 20.4 74 19.4 46 
13:42 22.0 74 21.9 31 
15:16 22.9 73 22.6 19 
17:19 20.7 74 21.6 28 
19:29 19.2 76 20.2 38 
21:37 17.9 77 18.4 49 
23:00 16.8 78 17.1 59 

 
Experiment shows that the measurement and control system can work well in the greenhouse environment. 
The greenhouse parameters changed mildly, which means that the greenhouse environment is properly 
controlled and suitable conditions are provided for crop growth.  

6. Conclusion  

The intelligent measurement and control system designed for greenhouse is capable of monitoring and 
controlling the blowers, sun screens, heating and humidifying devices as well as sky windows/side windows. 
The parameters of the greenhouse environment, including temperature, humidity and light intensity, are 
controlled within the desired range. Experiment has indicated that this system is high in technology content 
and low in cost, representing a breakthrough in automatic and intelligent control of greenhouses in China.  

Reference 

Chen J., 2014, The Greenhouse Control System Based on Embedded WinCE, Yinshan Academic Journal, 
Vol. 28, No. 1, pp. 44-47. 

Guo L.S., Xu X.N., Su L., 2013, Research on the Control System for Intelligent Greenhouse, Journal of 
Changsha University, Vol. 27, No. 2, pp36-38, doi: 10.3969/j.issn.1008-4681.2013.02.015. 

Hu H., Liang L.Z., 2014, Design of the Greenhouse Multi-point Temperature Gathering Based on Zigbee and 
ARM, Jiangsu Agricultural Sciences, Vol. 42, no.7, pp.414-419, doi: 10.3969/j.issn.1002-
1302.2014.07.143. 

Jiang D.G., 2014, GPRS-Based Designing Temperature and Humidity Monitoring System of Greenhouse, 
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Tan C.B., 2015, Research on Application of environment of greenhouse monitoring system based on ZigBee 
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Yin G., Zhao L., 2014, All intelligent greenhouse monitoring system design, Electronic Design Engineering, 
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