Gain
Mode value
Input voltage range
1
×
0
±
10 V
2
×
1
±
5 V
4
×
2
±
2.5 V
8
×
3
±
1.25 V
16
×
4
±
625 mV
32
×
5
±
300 mV
64
×
6
±
150 mV
128
×
7
±
75 mV
3.1.6
ADC Input Terminals Selection
Name
R/W
Type
Function
CHA_INMUX
R/W
u2
<1,2>
Selection of analog input terminals
The
ULAD 31
allows to select which pair of analog input terminals is connected to the
analog to digital converter. If value stored in CHA_INMUX is one (1) then IN1+/- termi-
nals are used for data acquisition. If the value is 2 then IN2+/- terminals are used. The
IN1 terminals are considered as main and this analog path is used for an factory device
calibration. The IN2 path is considered auxiliary for use where is required to check some
auxiliary state is monitored (i.e. pressure or temperature before sample analysis start) and
little worse noise parameters and calibration is not considered harmful.
3.1.7
ADC Sampling Period/Frequency
Name
R/W
Type
Function
ADCSAMPPER
R/W
u2
<10,100>
Sampling period specified in milisec-
onds
The
ULAD 31
is configured for 10 Hz (i.e. 100 ms) sampling rate which provides best
noise immunity to 60 Hz and 50 Hz AC mains frequency as well as other calibration and
ADC resolution parameters. The acquisition and control software reads ADC sampling fre-
quency from variable ADCSAMPPER to reflect connected device acquisition timing. The
value of the ADCSAMPPER can be modified to allow faster sampling rate if application
depends on that. Any value from 10 ms to 100 ms can be selected but voltage signal to
output value scaling is maintained only for rates given by next power of two series.
ADCSAMPPER value
Sampling frequency [Hz]
Sampling period [ms]
100
10
100
50
20
50
40
25
40
25
40
25
20
50
20
10
100
10
5