ROTRONIC MBW 373 - Manual (Page 18)

14
The time span is changed with the Numeric/Graphic menu.
1. Use the lower right menu key to select the Numeric/Graphic menu. ‘Numeric/Graphic’
appears on the key, and the key directly above it shows ‘Time Span’.
2. Press the Time Span key. A dialog box appears for entry of the desired time span.
3. Use the numeric keypad to enter a new value. As you press each numeric key, the numbers
appear in the white Change To field of the dialog box.
4. If you make an entry error, press the touch screen over the field that holds the number you
wish to change. Each time you press the touch screen there, the number backspaces one
digit. Use this technique to erase any unwanted digits, then continue with the keypad use.
5. Press the dialog box’s Ok button to accept the new value, or press Cancel to leave it
unchanged. Note that pressing enter on the keypad does the same as pressing the Ok
button.
The result will not be instant. It will take some time for the old data at the old time interval to be
replaced by data at the new time interval as determined by your selected time span.
Scaling
Each graph can have its own scaling (or y-axis) values. There are three distinctly different
scaling modes to choose from.
• Autoscale
Autoscale mode determines the scaling automatically so that all of the stored data will be visible
on the graph at the best possible resolution. As the range of the data changes, so does the
range of the graph. In autoscale mode, you can select a minimum that you want the graph to
scale to. This is very useful for data that is very stable with little variation. This prevents the 373
from setting the scaling to such a small range that even the highly stable data appears visibly as
wildly variable. For viewing dew or frost point graphs, setting this Autoscale Minimum to a value
of at least 0.2 or more is generally preferable. This allows the graph range to close in on the
data as it stabilizes at a point without becoming too narrow. You can experiment with this value
to determine your personal preferences with different parameters. Autoscale mode is the power
up default.
• Fixed Range
Fixed Range scaling allows you to select a fixed graph range, but automatically centered on the
current data point. In other words, as the current data varies so does the graph center point, but
the overall range remains fixed. This fixed range auto centering is mostly used to monitor data
for stability.
• MinMax
You can specify the minimum and maximum values used for the graph. This is completely fixed
scaling. If the data falls outside the minimum and maximum values you specify, you will not see
them on the graph. If you wish to see the data that is outside the values you specified, you’ll
need to specify minimum and maximum values with a larger spread.
You can change the graph scaling at any time, and freely switch between the three scaling
modes as well. Try it.
1. Using the touch screen, press directly on the graph you which to change. A graph scaling
dialog box will appear. One of the buttons in the Description column will have a green
indicator. That shows you the currently selected mode. Note that there are three buttons –
one for each mode.
2. Press the button of the mode you’d like to change to. Note that for the MinMax option, only
the Maximum button need be pressed (as Minimum is then automatically assumed).
3. Press the corresponding button in the Change To column for the range you selected.