Keithley 2657A, Reference Manual, Page: 115 / 805

In this section:
Relative offset .......................................................................... 3-1
Filters ....................................................................................... 3-2
Reading buffers ........................................................................ 3-6
Sweep operation .................................................................... 3-19
Triggering ............................................................................... 3-31
High-capacitance mode ......................................................... 3-63
Display operations .................................................................. 3-68
Digital I/O ............................................................................... 3-80
Relative offset
You can use the relative offset (REL) feature to set offsets to zero (0) or subtract a baseline reading
from present and future readings. With relative offset enabled, subsequent readings are the
difference between the actual input value and the relative offset value, as follows:
Displayed reading = Actual input
−
Relative offset value
Once a relative offset value is established for a measurement function, the value is the same for all
ranges. For example, if 50 mA is set as a relative offset value on the 120 mA range, the relative offset
value is also 50 mA on the lower current ranges. This can cause an overflow condition if the selected
range cannot accommodate the relative offset value.
When relative offset is enabled, the REL indicator turns on. Changing measurement functions
changes the relative offset value to the established relative offset value and state for that
measurement function.
Front panel relative offset
Enabling and disabling relative offset
The relative offset feature can be used to establish a zero (0) baseline. To enable and use this
feature, press the
REL
key. The reading (which becomes the relative offset value) is subtracted from
itself causing the meter to zero the display. The reading is then stored for use with subsequent
measurements. Pressing the
REL
key a second time disables the relative offset.
Defining a relative offset value
A unique relative offset value can be established for the selected measurement function.
Section 3
Functions and features