Actors |
Weather information system, Weather station |
Description |
The weather station sends a summary of the weather data that has been collected from the instruments in the collection period to the weather information system. The data sent are the maximum, minimum and average ground and air temperatures; the maximum, minimum and average air pressures; the maximum, minimum and average wind speeds; the total rainfall, and the wind direction as sampled at five-minute intervals. |
Stimulus |
The weather information system establishes a satellite communication link with the weather station and requests transmission of the data. |
Response |
The summarized data is sent to the weather information system. |
Comments |
Weather stations are usually asked to report once per hour but this frequency may differ from one station to another and may be modified in future. |
Actors |
Weather information system, Weather station |
Description |
The weather station sends a summary of its status to the weather information system. This includes details of the functioning of its instruments as tested by the self-test system and any other information about potential problems that have been detected. |
Stimulus |
The weather information system establishes a satellite communication link with the weather station and requests transmission of the status data. |
Response |
The weather station status data is sent to the weather information system. |
Comments |
Weather stations are usually asked to report once per hour but this frequency may differ from one station to another and may be modified in future. |
Actors |
Weather information system, Weather station |
Description |
The weather station should be in a shutdown state. The restart command causes all instruments to be initialized and the collection of weather data should begin. |
Stimulus |
The weather information system establishes a satellite communicaiton link with the weather station and issues a restart command. |
Response |
The weather station system should start up. |
Comments |
This should be rare. Normally, it is only required after the system software has been updated by a reconfigure command. |
Actors |
Weather information system, Weather station |
Description |
The weather station should be in an operational state. The shutdown command causes all collected data to be stored in permanent memory and theweather station instruments should then be shut down so that no further weather data is collected. |
Stimulus |
The weather information system establishes a satellite communication link with the weather station and requests the system to shut down. |
Response |
The weather station should shut down. |
Comments |
This should be rare. Normally, it is only required when the system software is to be updated. It should normally be preceded by a Report weather command. |
Actors |
Weather information system, Weather station |
Description |
The weather station should be in a shutdown state. The reconfigure command allows the existing software to be replaced by a software update which is remotely transmitted to the system. This is transmitted as a software download which is installed to replace the previous system. |
Stimulus |
The weather information system establishes a satellite communication link with the weather station and requests the system to accept a software download. |
Response |
After the download has been completed, the weather station should acknowledge that it has been correctly received and installed . |
Comments |
This command is used when software is to be updated. It must be preceded by a shutdown command and followed by a restart command. |
Actors |
Weather information system, Weather station |
Description |
The effect of this command is to run the weather station in a minimal energy state. The frequency of data collection is reduced, self-checking is only run once per day and instruments are turned off between data collection. |
Stimulus |
The weather information system establishes a satellite communication link with the weather station and requests the system to move to power saving mode. |
Response |
The weather station should acknowledge that it is in a power saving state. |
Comments |
This should be rare. Normally, it is only required when there has been some failure of the hardware that charges the weather station batteries. |
Actors |
Weather information system, Weather station |
Description |
This feature allows the weather station instruments to be controlled directly from the weather information system, rather than from the weather station control software. The system establishes a direct channel of communication to the instrument interface. Commands are received as a string, decoded and sent to the instrument being controlled. |
Stimulus |
The weather information system establishes a satellite communication link with the weather station and sends a string of instrument commands. |
Response |
The weather station should collect data as instructed by the commands. |
Comments |
This should be rare. Normally, it is only required when the system software has irretrievably failed. |