User manual

Chapter 3 Hardware Overview
NI 6034E/6035E/6036E User Manual 3-4 ni.com
Settling times can also increase when scanning high-impedance signals
due to a phenomenon called charge injection, where the analog input
multiplexer injects a small amount of charge into each signal source when
that source is selected. If the impedance of the source is not low enough,
the effect of the charge—a voltage error—will not have decayed by the time
the ADC samples the signal. For this reason, keep source impedances under
1kΩ to perform high-speed scanning.
Due to the previously described limitations of settling times resulting from
these conditions, multiple-channel scanning is not recommended unless
sampling rates are low enough or it is necessary to sample several signals
as nearly simultaneously as possible. The data is much more accurate and
channel-to-channel independent if you acquire data from each channel
independently (for example, 100 points from channel 0, then 100 points
from channel 1, then 100 points from channel 2, and so on.)
Analog Output
♦ NI 6035E and NI 6036E only
The NI 6035E device supplies two channels of 12-bit analog output voltage
at the I/O connector, and the NI 6036E device supplies two channels of
16-bit analog output voltage at the I/O connector. Each device has a fixed
bipolar output range of ±10 V. Data written to the digital-to-analog
converter (DAC) is interpreted as two’s complement.
Analog Output Glitch
In normal operation, a DAC output glitches whenever it is updated with
a new value. The glitch energy differs from code to code and appears as
distortion in the frequency spectrum.
Digital I/O
The NI 6034E/6035E/6036E device contains eight lines of digital I/O
(DIO<0..7>) for general-purpose use. You can individually
software-configure each line for either input or output. At system startup
and reset, the digital I/O ports are all high impedance.
The hardware up/down control for general-purpose counters 0 and 1 are
connected onboard to DIO6 and DIO7, respectively. Thus, you can use
DIO6 and DIO7 to control the general-purpose counters. The up/down
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