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4.5: Necessary conditions for correct connection and correct settings of the input of the
ADC L-502.
9.
In multi-channel mode, the optimal settling time n
su
(s.
) should be selected
depending on the output impedance of the signal source, the length and the
coherence of the cable.
It is suggested to choose the optimal
n
su
for this channel by the
criterion of obtaining a small inter-channel signal transmission from the previous polling
channel.
10.
To improve the signal-to-noise ratio and increase the resolution in the
measurement path, it is recommended to use the maximum possible averaging
factor n
av
> 1 (s.
for the required channel polling frequency and the necessary
signal conditioning time n
su
.
11.
Do not exceed the operating voltage ranges at the inputs X, Y, GND32 (s.
12.
Use the L-502 "common ground" operation mode only in case of closely located low-
resistance sources. Optimizing the
n
su
and n
av
settings for the "common ground" mode is
required. Do not make "common ground" connections through the cable, if there are no
low-resistance pull-up resistors on the L-502 side.
13.
While connecting L-502 "with common ground", the GND32 circuit must be in the same
group of cable wires (in particular, within the same screen) as other circuits X and Y
operating in the "common ground" scheme.
14.
While using 16 to 31 channels, it is advisable to combine L-502 "differential" and
"common ground" connections and settings to obtain more channels operating in
differential mode. In this case, the wires X and Y (differential circuit) and the wires X,
Y, GND32 ("common ground" circuits) should form different groups in the cable in a
common AGND circuit situation for these groups.
15.
When using L-502 without galvanic isolation, do not allow continuous currents on the
screens and common wires of the signal circuits. Do not allow continuous currents
between common-wire circuits of digital and analog signal circuits. Take into account
the internal scheme of land connection in L-502 (s.