Lake Shore Model 331 Temperature Controller User’s Manual
Linear (Continued)
Use the
s
or
t
key to toggle between the Linear B Variable: +SP1, –SP1, +SP2, –SP2, Value.
Press the
Enter
key to accept the new setting. You will see the next display.
Enter for Math A
Lin Equ B +0.0000
The Linear Variable B is entered using the numeric keypad, which includes the numbers 0
–
9, +/–,
and decimal point. Press the
Enter
key to accept the new setting.
Press the
Escape
key to return to the normal display or continue with the Filter settings (Paragraph
4.14.3).
4.14.3 Filter
The reading filter applies exponential smoothing to the sensor input readings. If the filter is turned on
for a sensor input, all reading values for that input are filtered. The filter is a running average so it
does not change the update rate of an input. Filtered readings are not used for control functions but
they are used for all input features including Max/Min.
The number of filter points determines how much smoothing is done. One filter point corresponds to
one new reading on that input. A larger number of points does more smoothing but also slows the
instruments response to real changes in temperature. The default number of filter points is 8 which
settles in approximately 50 readings or 5 seconds.
The filter window is a limit for restarting the filter. If a single reading is different from the filter value by
more than the limit the instrument will assume the change was intentional and restart the filter. Filter
window is set in percent of full scale range.
To configure a filter, continue from the Math Setup screen in Paragraph 4.14, press the
Enter
key
until the following display appears.
Select for Math A °®
Filter On
Use the
s
or
t
key to toggle between Filter On and Off. If you select Off, the routine will end and
return you to the normal display. If you select On, the routine will continue with the following.
Select for Math A °®
Filter Points 08
Use the
s
or
t
key to increment or decrement the Filter Points from 02 thru 64, with 08 being the
default. Press the
Enter
key. You will see the following display.
Select for Math A °®
Filter Window 01%
Use the
s
or
t
key to increment or decrement the Filter Window from 01% thru 10%, with 01% being
the default. Press the
Enter
key. You will return to the normal display.
4-28
Operation
