ROTRONIC MBW 373 - Manual (Page 17)

13
Display Parameters
Use the Parameters menu to select which parameters to display on the data lines. When you
select parameters for display on any of the five data lines, those selections remain valid until you
change them again, even if you turn the 373 off. See Selecting Parameters to Display on page 6
to select which values to display. A list of the available parameters follows. Note that not all
parameters are available on all systems since some systems may not contain the associated
hardware components.
Dew Point
Frost Point
%RH
%RH WMO
Volume Ratio
Weight Ratio
Absolute Humidity
Specific Humidity
Vapor Pressure
Atmospheric Pressure
Head Pressure
Flow Rate
External Temperature
Head Temperature
Precooler Temperature
Block Temperature
Internal Tube Temperature
External Tube Temperature
Mirror Temperature
Graphing Data
Any value that you can view numerically can also be viewed as a graph at any time. The 373
automatically maintains a short history of each and every selectable parameter so that a graph
may be seen instantly whenever a data line is toggled from a numeric mode to a graph mode.
Selecting Between Numeric Data and Graph
Selecting between numeric and graph modes is done with the Numeric / Graphic menu. See
Selecting Graph vs. Numeric Data on page 6.
Changing Graph Attributes
You can change the overall time span (or x-axis) and the scaling (or y-axis) attributes of graphs.
Time Span
Changing the time span allows you to see a longer or shorter history period for the data. The
373 stores a fixed number of data points independent of the selected time span. Changing the
time span changes the interval used for data storage. With a 15 minute time span, the graph
data is sampled and stored every few seconds. However, with a 2 hour time span, the graph
data is only sampled, stored, and updated about once a minute.
When you change the time span, the old data previously sampled and stored at the old interval
will be incrementally replaced by new data sampled at the new interval. The Time Span as
indicated on the graph will always reflect the actual time span of the currently stored data, and
will eventually agree with the time span you select. The selected time span is common to all
graphs so that they all have the same time relationship to one another.