Campbell LoggerNet, Instruction Manual

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Appendix A. Glossary of Terms
P
Packet – a unit of information sent between two BMP or PakBus devices that
are communicating. Each packet can contain data, messages, programming,
etc. Usually contains addressing and routing information.
PakBus – A packet-based and packet-switched networking protocol used by
newer dataloggers. PakBus allows for robust transmission of commands and
data, dynamic routing between PakBus devices, and peer-to-peer
communications (such as when one datalogger needs to control another
datalogger without involving the PC).
Parameter – Number or code which helps to specify exactly what a given
datalogger instruction is to do.
Path – The modems, or other devices that make up a link to communicate with
a remote site datalogger.
Polling – Process where a datalogger or other communications device is
periodically checked for any packets it needs to send. The server polls
dataloggers for most communications links. Some communications devices,
such as RF232T radio bases or repeaters can also poll datalogger sites.
Polling Interval – The user-specified interval that determines when to poll a
given device.
PrgmFree – An entry in the status table that shows the amount of remaining
program memory, in bytes.
PrgmSig – An entry in the status table that shows the signature of the
datalogger program. The signature is a unique number derived from the size
and format of the datalogger program.
PromID – An entry in the status table that shows the version number of the
datalogger PROM or OS.
PromSig – An entry in the status table that shows the signature of the
datalogger PROM or OS. As with the PrgmSig, if this signature changes, the
datalogger instruction set has somehow been changed.
Processing Instructions – Datalogger instructions that further process input
location data values and typically return the result to Input Storage where it can
be accessed for output processing. Arithmetic and transcendental functions are
included in these instructions.
Program Control Instructions – Datalogger instructions that modify the
sequence of execution of other instructions in the datalogger program; also
used to set or clear user flags.
Program Signature – A program signature is a unique value calculated by the
datalogger based on program structure. Record this signature in a daily output
to document when the datalogger program is changed.
Program Table – The area where a datalogger program is stored.
Programming in Edlog dataloggers can be separated into two tables, each
having its own execution interval. A third table is available for programming
subroutines that may be called by instructions in Tables 1 or 2. Programming
in CRBasic dataloggers can be separated into different “scans”. The length of
the program tables or scans is constrained only by the total memory available
for programming.
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