Rel Key - Keithley 6514 Quick Manual

12 Model 6514 Quick Results Guide
With both filters enabled, the median filter operation is performed first. After the median
filter yields a reading, it is sent to the stack of the digital filter. Therefore, a filtered reading
will not be displayed until both filter operations are completed.
The settings for the filter are global. Therefore, the filter configuration applies to all four
measurement functions. The MEDN key is used to configure and control the median filter,
and the AVG key is used to configure and control the digital filter. When either the median
or digital filter is enabled, the FILT annunciator is on.
Median filter
The median filter is used to determine the "middle-most" reading from a group of readings
that are arranged according to size. The number of sample readings used for the median
calculation is determined by the selected rank (1 to 5) as follows:
Sample readings = (2 × R) + 1
where: R is the selected rank (1 to 5)
To configure the median filter, press the MEDN key to display the present filter rank. Then
use the RANGE keys to display the desired rank (1 to 5), and press ENTER.
Digital filter
The digital filter type can be either moving or repeating. With the moving filter, each time
a reading conversion occurs, the readings in the stack are averaged to yield a single filtered
reading. The stack type is first-in, first-out. After the stack fills, the newest reading
conversion replaces the oldest. Note that the instrument does not wait for the stack to fill
before releasing readings. With the repeating filter, the unit takes a selected number of
reading conversions, averages them, and yields a reading. It then flushes its stack and
starts over.
To configure the digital filter, press the AVG key, (the set the number of readings to
average (1-100)). Choose the repeat or moving average type, then press ENTER.

REL key

The REL key nulls an offset or subtracts a baseline value from future readings. Note that
the rel value is the same for each measurement range. For example, a rel value of 1V on
the 2V range is also 1V on the 20V and 200V ranges.
Perform the following steps to set a rel value:
1.
2.
3.
Display the reading you want as the rel value. This could be a zero offset reading
that you want to null out, or it could be an applied level that you want to use as a
baseline.
Press REL. The REL annunciator turns on, and subsequent readings will be the dif-
ference between the actual input and the rel value.
To disable REL, press the REL key a second time. The REL annunciator turns off.