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Quick Reference Guide
Filter
The Model 2182 has an analog filter and a digital filter. When Filter is enabled by pressing
the FILT key (FILT annunciator on), it assumes the combination of analog and digital filter
configuration for the present measurement function (DCV1, DCV2, TEMP, TEMP2).
Filter state (enabled or disabled) and configuration is saved by each function.
Analog filter
With the low-pass Analog Filter ON, the normal-mode noise rejection ratio of the
instrument is increased at 60Hz. This filters out noise induced by the power line. The
analog filter attenuates frequency at 20dB/decade starting at 18Hz.
A primary use of the analog filter is to keep the high-gain input stage of the Model 2182
from saturating due to the presence of high AC and DC voltage. Note, however, that the
filter only attenuates AC voltages for the 10mV range of the Model 2182.
Digital filter
The digital filter is used to stabilize noisy measurements. The displayed, stored, or
transmitted reading is a windowed-average of a number of reading conversions (from 1 to
100).
In general, the digital filter places a specified number of A/D conversions (Filter Count)
into a memory stack. These A/D conversions must occur consecutively within a selected
reading window (Filter Window). The readings in the stack are then averaged to yield a
single filtered reading. The stack can be filled in two ways (Filter Type): moving or
repeating. The moving filter keeps adding and removing a single A/D conversion from the
stack before taking the average, while the repeating filter only averages a stack that is
filled with new A/D conversions.
Configuring filters
To configure the filters, press SHIFT TYPE, and then choose your selections as needed.
You can turn the analog and digital filters ON or OFF, and set digital filter window, count,
and select average or repeat type filters. See Section 3 of the Model 2182 User's Manual
for details on filter parameters.
REL key
The REL key sets a rel value for the selected function (DCV1, DCV1, TEMP1, and
TEMP2). Note that a unique rel value can be established for each measurement function.
Perform the following steps to set a rel value:
1.
Display the reading you want as the rel value. This can be a zero offset reading that
you want to null out, or it can be an applied level that you want to use as a baseline.
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