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Chapter 2
Operating the NI 435x Device
Choosing a Range
Note
With VirtualBench-Logger or the MAX Create New Channel Wizard, you can
specify the range based on the sensor type in engineering units appropriate to the sensor.
This sensor range is used to automatically set the actual hardware range.
Choosing a Reading Rate
NI 435x User Manual
The volts mode has six bipolar input ranges: ±625 mV, ±1.25 V, ±2.5 V,
±3.75 V, ±7.5 V, and ±15 V.
The 4-wire ohms mode has six corresponding input ranges when used with
the built-in 25 µΑ current source: 25 kΩ, 50 kΩ, 100 kΩ, 150 kΩ,
300 kΩ, and 600 kΩ, and 625 Ω, 1.2 kΩ, 3.75 kΩ, 7.5 kΩ, and 15 kΩ
with the built-in 1 mA current source on the NI PXI-4351 or NI PCI-4351.
Choose the smallest range for the best measurement results. When
scanning multiple channels, the NI 435x uses a single range, which is the
widest range of any channel in the scan list.
The reading rate is the rate at which the NI 435x takes a new measurement.
This rate has a direct relationship with the digital filter built into the ADC
used in the NI 435x.
The digital filter has the characteristics shown in Figure 2-1. You can set the
frequency of the first notch of this filter to 10 Hz, 50 Hz, or 60 Hz. Setting
the notch filter at one of these frequencies rejects any noise at that
frequency as well as at all of its multiples.
0
–20
–40
–60
–80
–100
–120
0
10
Figure 2-1. Digital Filter Characteristics for 10 Hz Setting
20
30
Frequency (Hz)
2-2
40
50
60
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