Campbell Scientific CR9000X Measurement and Control System - Manual (Page 430)

Appendix E. Glossary
UPS uninterruptible power supply. A UPS can be constructed for most
datalogger applications using AC line power, an AC/AC or AC/DC wall
adapter, a charge controller, and a rechargeable battery.
User Program The CRBASIC program written by the CR1000 user in
CRBASIC Editor or Short Cut.
variable A packet of CR1000 memory given an alpha-numeric name, which
holds a potentially changing number or string.
VAC Volts Alternating Current. Mains or grid power is high-level VAC,
usually 110 VAC or 220 VAC at a fixed frequency of 50 Hz or 60 Hz.
High-level VAC is used as a primary power source for Campbell
Scientific power supplies. Do not connect high-level VAC directly to the
CR1000. The CR1000 measures varying frequencies of low-level VAC
in the range of ±20 VAC.
VDC Volts Direct Current. The CR1000 operates with a nominal 12 VDC
power supply. It can supply nominal 12 VDC, regulated 5 VDC, and
variable excitation in the ±2.5 VDC range. It measures analog voltage in
the ±5.0 VDC range and pulse voltage in the ±20 VDC range.
volt meter an inexpensive and readily available device useful in
troubleshooting data acquisition system faults.
Volts SI unit for electrical potential.
watch dog timer an error checking system that examines the processor state,
software timers, and program related counters when the datalogger is
running its program. If the processor has bombed or is neglecting
standard system updates or if the counters are outside the limits, the watch
dog timer resets the processor and program execution. Voltage surges
and transients can cause the watch dog timer to reset the processor and
program execution. When the watch dog timer resets the processor and
program execution, an error count is incremented in the watchdog timer
entry of the status table. A low number (1 to 10) of watch dog timer
resets is of concern, but normally indicates the user should just monitor
the situation. A large number (>10) of error accumulating over a short
period of time should cause increasing alarm since it indicates a hardware
or software problem may exist. When large numbers of watch dog timer
resets occur, consult with a Campbell Scientific applications engineer.
weather tight describes an instrumentation enclosure impenetrable by
common environmental conditions. During extraordinary weather events,
however, seals on the enclosure may be breached.
XML Extensible Markup Language.
E-10