timing by which the Central Hydrological System gathers data from a
Normal Poll – Data values requested from the remote
outstation once every 24 hours.
SEPA Normal Poll – Data values requested from the remote outstation once every 24 hours.
SEPA Event Poll – Data values requested from the remote outstations once every 60 minutes for a period of 2 days.
SEPA Alarm Dial Up – The alarm condition messages which are reported from the remote outstations on occurrence.
DARDNI Normal Poll – Data values requested from the remote outstations once every 7 days.
DARDNI Voice Message Poll – Telephone calls made to the remote outstations which generate automated voice messages which provide the status and values of the measured hydrometric items on a particular site.
|Protocol||The structured method by which data is retrieved from a site. Generally each remote outstation supplier provides their own proprietary communications protocol.|
|DNP3||A new standard protocol which can be used across a wide range of remote outstations from different suppliers.|
|PSTN||Public switched telephone network|
|GSM||Second generation mobile phone networks|
|GPRS||General Packet Radio Service – provided on mobile phone networks.|
|TG1150||The existing remote outstation type used within SEPA|
|D7000||A new range of remote outstations which SEPA are assessing for the future.|
|Data Logger||A particular type of remote outstation used for on site recording of data. SEPA have a number of Dynamic Logic TG 1150 outstations and Isodaq data loggers and DARDNI have a number of OTT data loggers.|
|Portability||A term used to describe the capability of equipment to deployed and then re-deployed as required at different sites.|
|Baud Rate||The data transfer rate from the remote outstation to the central gathering system measured in digital bits per second.|
|Instrument||The field device which is used to measure the required site data, such as river flow, river levels, water quality and rainfall.|
|Geo-referencing||Assigning co-ordinates to an image file, usually by inputting the co-ordinates of known or prominent features.|
|NPV||This is the summation of the 15-year life cycle annual stream of discounted total costs, for each communication technology, giving the equivalent total value for today. This is done by discounting the 15-year life cycle annual costs using an appropriate discount rate, which for this project will be 3.5%.|
|CDMA||Code Division Multiple Access: A technology for digital transmission of radio signals between, for example, a mobile telephone and a radio base station. In CDMA, a frequency is divided into a number of codes.|
|SWOT||An Options Analysis process. The SWOT methodology allows the strengths, weaknesses, opportunities and threats to be listed and then compared.|
energy density of a battery is the amount of energy a kilogram weight
of a battery could deliver, it is expressed in watt-hours per
|Discharge rate||The discharge rate of a battery is often expressed in terms of the C-rate. This is the current drain that would discharge a battery in one hour. This would, usually, be a very high load to impose on a battery and effects characteristics such as the discharge curve so most battery manufacturers provide data for a reduced discharge rate of 0.2C or 0.1 C. Consequently care is needed when comparing data from different manufacturers.|