Generalization of different telecommunication systems in Poland today, gives a chance to the technological companies to provide totally new services as well as the regular ones but of better quality and lower price. Among modern ways of data exchange one should especially concentrate on cellular telephony and internet mainly because they are so widely accessible. Integration of the mentioned above technologies created a communication platform, which has a lot of their advantages: openness, flexibility, mobility and above all low exploitation cost.
Telemetry is a domain of technology, which deals with taking
measurements at a distance. In the telemetric systems one can
distinguish two basic subsystems such as: meteorological subsystem and
data transmission subsystem. The tele transmission should allow on
creating an information channel in which it is possible to send the
measurement data to the measurement devices to a place where they are
collected and processed and eventually to a return channel allowing for
an operator to have influence on the work of meteorological subsystem.
The company LAB-EL produces the measurement devices and specializes in the environment parameters’ measurements. In the past few years our company created few systems based on the electronic converters cooperating with the equipment for registry and transmission. Our systems are used both in closed spaces (warehouses, industry halls) as well as in the field conditions (automatic climate stations). Data transfer from the sensors to an operator can be realized using a classic cable connection or a radio transmission, which usually is necessary in cases of field and mobile objects. Typical wireless transmission solutions deal with using the existing infrastructure and the services offered by the cellular telephony operators. Data is sent between the register and the collecting stand using GSM or GPRS modems. The most effective method at this point of time used for creating a connection between a field and a stationary object is by using IP network (internet) along with GPRS transmission ( general packet radio service). The way in which such tele transmission system works is described below.
A measurement station is located in the field - in a place where a cable communication link cannot be established. The station consists of: set of sensors (i.e.: hytherograph LB-710, wind meter LB-746, rain gauge ARG-100 etc.), a controller (i.e. LB-741), which is also treated as a recorder and a sending/ receiving GPRS module (i.e. cellular telephony modem LB-430). The station controller in set time intervals establishes a connection with a local cellular telephony operator, who provides it with an IP number. The station controller is at that point of time a node in the internet network and can send data to any location in the network. It then formats an information package (UDP) and sends it. The package reception place is a computer working in the IP network equipped with software realizing decoding and registry. On the other hand the same computer realizes upon the operator's (client's) request data processing and visualization services. The operator using a standard www explorer on a computer connected to the network can request posting or exporting of the collected data. The user has a possibility of choosing:
|Data transmission from a field meteorological station - scheme|
Additional controller function is informing about the system status. After detecting a situation requiring operator’s intervention a special alarm package is sent to a server. The information can be sent further along to the operator in a form of SMS message.
Example system visualizations working in accordance with the discussed rule are introduced on the pages: