
Chapter 14 SCXI Hardware
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National Instruments Corporation 14-9 DAQ Hardware Overview Guide
other 32 input channels during a hardware-controlled scan. On each
channel, including CJTEMP, the SCXI-1102 has a 3-pole lowpass filter
with a 2 Hz cutoff frequency to reject 60 Hz noise. Each of the 32
differential analog input channels, but not CJTEMP, also has an amplifier
with a selectable gain of 1 or 100, selected through the
SCXI_Set_Gain
function. The amplification and filtering occur before multiplexing.
Note When you change the gain on a channel, the output will take several seconds to
settle. The module contains a Status Register to indicate that the output is in the process of
settling, and this information is available to applications through the
SCXI_Get_Status
function.
The SCXI-1102 supports multiplexed operating mode only; it does not
support parallel mode.
The SCXI-1102B and the SCXI-1102C are variants of the SCXI-1102.
They are functionally identical to the SCXI-1102 except for their
higher bandwidth support: 200 Hz for SCXI-1102B and 10 kHz for the
SCXI-1102C, as compared to the 2 Hz bandwidth limitation for the
SCXI-1102.
SCXI-1104/C
The SCXI-1104/C has 32 differential analog input channels that you can
select through the
SCXI_Single_Chan_Setup function. The SCXI-1104
has a 3-pole lowpass filter with a 2 Hz cutoff frequency on each channel to
reject 60 Hz noise. The SCXI-1104/C has a 3-pole lowpass filter with a
10 kHz cutoff frequency on each channel. Each of the 32 differential
analog input channels also has an amplifier with a fixed gain of 1. There is
a divide-by-10 resistor network before the amplifier inputs so the effective
gain on all channels is 0.1. The amplification and filtering occur before
multiplexing.
SCXI-1112
The SCXI-1112 has eight differential analog input channels and one
cold-junction sensor channel (CJTEMP) for each analog input channel
<CJTEMP0...CJTEMP7> that you can select through the
SCXI_Single_Chan_Setup function. The module can multiplex
CJTEMP with the other eight input channels during a hardware-controlled
scan. On each channel, including the CJTEMP, the SCXI-1112 has a 3-pole
lowpass filter with a 2 Hz cutoff frequency to reject 60 Hz noise. Each of
the eight differential analog input channels, but not the CJTEMP channels,
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