Campbell Scientific PC400 Datalogger Support Software - Manual (Page 222)

Appendix A. Glossary of Terms
SDI-12 – SDI-12 stands for Serial Digital Interface at 1200 baud. It is an
electrical interface standard and communications protocol that was originally
developed by Campbell Scientific and other manufacturers for the U.S.
Geological Survey for hydrologic and environmental sensors. SDI-12 was
designed to be a simple interface (ground, 12 volts, and signal) that improves
compatibility between dataloggers and “smart” microprocessor-based sensors.
Other goals of the SDI-12 standard are:
• low power consumption for battery powered operation via the datalogger
• low system cost
• use of multiple sensors on one cable connected to one datalogger
• allow up to 200 feet of cable between a sensor and a datalogger
Security Code – A code entered into the datalogger either directly with a
keypad or via the datalogger’s program to prevent unauthorized access to
datalogger settings, programs, and data.
Server – Also “communication server”, a software application that accepts
connections from client applications and provides data or other information as
requested. The LoggerNet server manages all the communications and data
collection for a network of dataloggers. The collected data is made available
for client applications. PC200W and PC400 also use the communication server
but in a more limited configuration.
Short Cut – A program generator application that ships with PC400,
LoggerNet, and is available as a stand-alone product from the Campbell
Scientific website. Short Cut does not require knowledge of individual program
instructions. Users need only know what kind of datalogger and sensors they’re
using and decide what output they require. Short Cut generates the program for
them. (Contrast a “program generator” with the full-featured “program
editors”, Edlog and CRBasic Editor.)
Signature – Number calculated to verify both sequence and validity of bytes
within a packet or block of memory.
Single-ended Analog Input – Some analog sensors have only one signal wire.
(They will also have another wire that can be grounded and that is used as the
reference for the signal wire.) With this type of sensor, only one analog
connection is required. Hence, it needs a “single-ended” or SE analog input.
The single ended channels are marked as SE on the datalogger wiring panel.
Socket Data Export – a software application that connects to the LoggerNet
server and provides a TCP/IP socket for a user created application to receive
data records from the server data cache.
Station – A datalogger site is often referred to as a station.
Station Number – The LoggerNet server assigns and uses station numbers for
routing packets to the dataloggers. These numbers can be modified using
CoraScript. Not to be confused with datalogger serial numbers, PakBus
addresses, or addresses set in communications peripherals such as RF or MD9
modems.
Storage – An entry in the status table that shows the number of final storage
locations available.
Synchronous – The transmission of data between devices occurs as groups of
zeros and ones. For the data to be “read” correctly, the receiving device must
begin reading at the proper point in the series. In synchronous communications,
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