WEATHERPAK
®
-2000 USER
MANUAL
Coastal Environmental Systems (206) 682-6048
- 10 -
GLOSSARY
ALOHA:
Aerial Location of Hazardous Atmospheres
ASCII:
American Standard Code for Information Interchange.
Autoboot:
Automatic bootup.
Base Mount:
A shortened name for the “quick-release base mount”, the device which holds the WEATHERPAK
and provides electrical interface.
Boot or Bootup:
When a computer initializes itself and automatically starts operation of a program when the
power is turned on or after a warm reset.
Byte:
A group of eight bits of computer information.
CAMEO
: Computer Aided Management of Emergency Operations
Declination
: See Variation.
Dorn Fittings:
Compression fittings that allow an electronic cable to penetrate a casing wall and maintain a
hermetic seal.
EEPROM:
Electronically Erasable Programmable Read-Only Memory--- allow programmable setting of system
parameters that is preserved when all power is removed.
Magnetic declination:
See Variation.
Magnetic variation:
See Variation.
RAM:
Random Access Memory -- memory for data storage and program operation. RAM can be written to and read
by addressing from the microprocessor.
RC Filter:
An analog low-pass filter made of resistors and capacitors.
Resolution:
The smallest amount of change in a measured quantity that can be discerned in a measurement.
Unless stated otherwise, resolution implies the “exported resolution” which is the least resolvable change in the
final datum. As an example, temperature might be reported to 0.1
C but the actual measurement and internal
processing might maintain 0.01
C resolution. I
n this case, the resolution would be 0.1
C. (sometimes written
±0.1
C).
RFI:
Radio Frequency Interference -- any noise that enters into a system from external sources.
RS232:
The most common computer serial interface standard.
Tranzorb:
A special diode semiconductor device that will acts as a short to high-voltage transients. It is installed
on electrical input or output connections to protect a device from corona or electrical transients such as lightning.
Variation:
Also magnetic variation and deviation. At most points on the Earth, the direction to true north varies
from the direction to magnetic north by some number of degrees. This difference is called the
magnetic
declination
. When the local magnetic anomalies are added to the declination, the result is called the
magnetic
variation
or simply the
variation
. Either term, declination or variation, is correct although surveyors generally
prefer the term declination and navigators the term variation.
Aeronautical and marine charts give variation as isogonic lines, or lines of constant magnetic variation. Variation
changes with time, and the charts usually give the rate of change. In some areas, such as the Arctic, the charts note
that compass measurements are unreliable. For the highest accuracy, it is important to use up-to-date charts. When
a compass needle points east of true north it is due to
easterly variation
. This is the case for most of the
continental U.S.A. The correction from magnetic to true direction for an easterly variation is a positive correction.
As an example, in Seattle WA the variation is approximately 22
°
and a compass reading of 0
°
Magnetic
corresponds to a true direction of 22
°
True. Alternatively, a
western variation
results in a negative correction.
Vector Averaging:
The technique for averaging a wind or ocean current by converting each measured speed and
direction pair to a corresponding pair of x-y coordinates for averaging. The coordinates are summed over an
averaging interval and their final average is computed at the end of the averaging time. Vector averaging removes
the errors that occur when direction cycles from 359
°
to 0
°
.
Warm Reset:
A system reset whereby the computer is reset and restarted but all peripherals remain powered.
Watchdog Timer:
A special countdown timer whose function is to cold or warm reset a system if its computer
program stops operating. Often during lightning or intense RFI a computer RAM will be corrupted and the
program will “crash”.