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The Controlant Monitoring System is an automatic wireless monitoring system, which is used in various applications where automatic measurements of environmental variables (e.g. temperature, humidity) are required.

The basis of the system is a star-shaped wireless network where multiple wireless loggers can transmit measurements to a gateway unit which sends the data to a central database server via the mobile network. The data can then be accessed from an internet connected computer from a web browser interface.

Controlant wireless loggers run on a battery. The gateways have a rechargeable internal backup battery which can keep the system running for 12-24 hours (depending on usage) in case of power failure. The battery is a rechargeable lithium-ion battery.

 

System Overview

 

 

 

Figure 2: Overview of the Controlant wireless monitoring system

Multiple loggers can be located on each location, connecting to one or more gateways. Data from multiple locations is gathered in a database, where customers can access it in a single interface.

 

 

Theory of Operation

 

 

Figure 3: Block diagram of the Controlant wireless system

 

A functional block diagram for the CO 13.01 wireless logger is shown in Figure 3. The RF module CC1101 is a low-power sub-1 GHz RF transceiver operating in the 868 MHz to 915 MHz ISM band.

The system has two operating modes. The first operating mode is at a symbol rate of 4.75 kbps, and a bit rate of 38 kbps. GFSK modulation is used with 20 kHz deviation. This operation mode is used for all communications in the 868MHz band as well as for FHSS mode in the 915 MHz band. The second operating is at a symbol rate of 475 bps, and a bit rate of 4 kbps. 2-FSK modulation is used with 550 kHz bandwidth. This operation mode is used for all synch package communication in the 915 MHz band.

A 3.6 VDC battery is supplied to the RF module. The module transmits with a maximum power of 11 dBm into an external antenna. This module does not transmit for more than 54 ms over any 1 s time period and fulfills all duty cycle limits on the 868MHz band and uses 121 channels for FHSS in the 915 MHz band with 200 kHz channel spacing and 75 kHz channel bandwidth (20 dB).

Logger Operation

The purpose of the Controlant wireless logger is to measure environment variables such as temperature and humidity. The loggers automatically transmit measurements to a nearby gateway, which forwards the data to a central database.  The wireless sensor communicates with the gateway on the license free ISM bands (868 MHz for EU and 915 MHz for North America). 

 

System Components

The system consists of following devices, software and systems:


  • Database


  • User Interface

 

 

 

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