FSC[2:0] = 400000h
´
Expected RMS Value
Actual RMS Value
FSC[2:0] = 400000h
´
Expected Output Code
Actual Output Code
SBAS418I – SEPTEMBER 2007 – REVISED MARCH 2015
9.30 User Calibration
User Calibration (continued)
System calibration of the ADS1282 can be performed
The value written to the FSC registers is calculated
without
using
the
calibration
commands.
This
by
procedure requires the calibration values to be
externally
calculated
and
then
written
to
the
DC signal calibration is shown in
. The
calibration registers. The steps for this procedure are:
expected output code is based on 31-bit output data.
1. Set
the
OFSCAL[2:0]
register
=
0h
and
GANCAL[2:0] = 400000h. These values set the
offset and gain registers to 0 and 1, respectively.
(11)
2. Apply a
zero
differential input to the input of the
system. Wait for the system to settle and then
For ac signal calibration, use an RMS value of
average
n
output readings. Higher numbers of
collected data (as shown in
averaged readings result in more consistent
calibration. Write the averaged value to the OFC
(12)
register.
3. Apply a differential dc signal, or an ac signal
(typically full-scale, but not to exceed 103% full-
scale). Wait for the system to settle and then
average the
n
output readings.
Copyright © 2007–2015, Texas Instruments Incorporated
31
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