CEMP Instrumentation

The sensors are monitored with a datalogger. Sensors are sampled every 3 seconds and summarized by the datalogger for each 10 minute period. Current data readings are displayed at each station with an LCD display mounted into the door of the datalogger enclosure. The display is updated every 6 seconds. The current readings include: gamma radiation (uR/hr), air temperature (°F), humidity (%), wind speed (mph), wind direction (direction octant), solar radiation (ly), station barometric pressure (in.Hg.), precipitation since midnight (in.), and system battery voltage (volts).

The summarized 10-minute data (hourly for satellite telemetered stations) consists of the following parameters:

Element

Statistic

Solar Radiation (lg) average
Wind Speed (mph) average
Wind Vector magnitude (mph) vector average
Wind Vector direction (degrees) vector direction
Standard deviation of direction (degrees) std. dev.
Max. Wind Gust (mph) maximum sample (3 sec.)
Max. Air Temperature (F) maximum
Ave. Air Temperature (F) average
Min. Air Temperature (F) minimum
Max. Relative Humidity (%) maximum
Ave. Relative Humidity (%) average
Min. Relative Humidity (%) minimum
Barometric Pressure (in.Hg) average
Precipitation (in.) total for 10 min.
Precipitation (in.) running total (in.), sample
Max. Gamma Radiation (uR/hr) maximum
Ave. Gamma Radiation (uR/hr) average
Min. Gamma Radiation (uR/hr) minimum
Max. Battery Voltage (volts) maximum
Ave. Battery Voltage (volts) average
Min. Battery Voltage (volts) minimum
Datalogger temperature (F) average
Station ID sample

 

Data telemetry from the stations occurs via conventional telephone landline, cellular phone or GOES satellite. Due to the remoteness of 5 of the ranch stations, one-way satellite telemetry was the most viable method to telemeter the data. Data for these stations are summarized into hourly periods and telemetered once every 3 hours. The GOES DCP system assigns specific transmission intervals and times to each platform. Since the satellite telemetry is only one-way (to DRI), data is stored on-site for later retrieval. Hourly and 10-minute data values are stored using data storage modules and downloaded during routine maintenance visits. After the data is retrieved, it is uploaded to the CEMP website.

Cellular phone service is used at locations where phone landlines are unavailable or installation costs are excessive. In the event of communication failure with a particular site during a data call, the data is stored by the datalogger and then retrieved on the subsequent call. During a normal calling cycle, each site that experiences a communication failure receives at least one call-back attempt. In case of an extensive failure in any of the communications systems, on-site data storage is designed to allow for 20 days of storage on the datalogger. Telephone and cellular phone access also permit the reprogramming of the remote units without a station visit.