
2-6
Functional Description
Note:
Analog input channels on DAS-8 Series boards are provided with
protection against signals outside the specified analog input range. All
DAS-8 Series boards can tolerate voltages up to ±35V and transients of
several hundred volts without damaging the board.
When measuring signals at differential inputs, DAS-8/PGA(G2) and
DAS-8/AO boards can tolerate common-mode voltages up to ±35V and
transients of several hundred volts without damaging the board; however,
for normal operation of the board, make sure that the common-mode
voltage is no more than 12V
−
((
G
/ 2) x
V
D
), where
G
is the gain and
V
D
is the differential input voltage.
The DAS-8/PGA(G2) and DAS-8/AO support voltage input ranges from
±10 volts to ±0.01 volts (bipolar) and +10VDC to 0.02VDC (unipolar).
Higher voltages may be measured by the use of simple resistive dividers.
Each DAS-8/PGA(G2) or DAS-8/AO input channel can be configured for
either single-ended or differential inputs by means of Switch S2. The
DAS-8/PGA(G2) has a built-in differential amplifier to minimize errors
from Common Mode voltages. A DAS-8/PGA(G2) input channel should
be configured for single-ended (SE position of SW2 for each channel)
when attempting to measure floating signals. Grounded signals should be
read in the differential configuration to reduce common-mode error.
When using the DAS-8/PGA(G2) and DAS-8/AO with the EXP-16, all
DAS-8/PGA(G2) and DAS-8/AO channels should be set for single-ended
inputs.
The DAS-8 and DAS-8/LT provide a +10V A/D voltage reference (Vref).
It may be used for offsetting signals, but should not be heavily loaded.
The maximum available output current is 2mA. Since this reference is
shared by the A/D, any overload or shorting of the reference will affect
the scaling of the A/D.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com