Vaisala Spectrum 4.0 - Manual (Page 77)

Veriteq Spectrum 4.0 User’s Guide
71
R–T
Logger file A file that is created after transferring a logger’s data to the PC. The file con-
tains the collected readings (from all active channels) for the transferred log-
ger, including the logger’s description, model number, serial number,
firmware version number, file description, Local time, and UTC (Universal
Time Coordinated) time. Logger files are identified by their .spl extension (for
example, PRIMARY_GAS_FLOW.spl). Logger files cannot be viewed
directly—you have to insert the Logger file into a Graph file before the data is
displayed as a graph.
NIST An acronym for the National Institute of Standards and Technology.
Range Normal operating limits, specified by the lowest calibration point to the high-
est calibration point.
Relative humidity Relative humidity is the measure of the amount of water vapor in the air com-
pared to how much it can possibly hold at that temperature. A relative humid-
ity of 50% means that the air contains only one-half as much water as it could
possibly hold. The capacity of air to hold water is heavily dependent on the
temperature of the air. The colder the air, the less water it can hold. Air at
50°F can hold only one-quarter the amount of water as air at 95°F.
Sample A measurement reading that is stored to data logger’s memory.
Sample smoothing
(deadband) A setting in Spectrum (Tools>Options>Insert tab - Sample smoothing) that
controls how the samples in a logger file are interpreted when they are
inserted into a graph. Sample smoothing (or sample deadband) is the mini-
mum change in the input signal required to cause a change in the displayed
channel values. Sample smoothing is used to dampen the effects of noise,
and is defined in terms of raw analog-to-digital converter counts.
Sample interval The sample interval is the rate at which the logger takes and records readings
to memory. The sample interval applies to all enabled channels on the logger.
You may want to occasionally change the sample interval on the logger
because:
• Faster sample rates may be required by the application.
• You need to record readings over a longer duration.
• You want to minimize the collection of unnecessary data.
Scale The range of values a graph displays.
Serial port The communications port to which you can attach devices such as a modem,
mouse, or serial printer to the computer. The serial communication ports on
the computer are commonly referred to as COM1, COM2, COM3, and so on.
Serial ports exchange data sequentially, one unit at time.
Stability The ability of a sensor or measurement instrument to maintain its perfor-
mance characteristics over a specified period of time.
Thermistor A temperature-sensing element (a thermally-sensitive resistor) composed of
sintered semiconductor material that exhibits a large change in resistance in
proportion to a small change in temperature. The relationship between tem-
perature and resistance is approximated for most thermistors by the Stein-
hart-Hart equation.
Traceable Capable of being traced back to a recognized measurement standard or ref-
erence.