© National Instruments Corporation
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2-15
Use the following equation to determine the ADC conversion rate and timing mode based on a
given sample rate:
You can determine the ADC timing mode by coercing the ADC conversion rate to the next
largest rate using the values in Table 2-5.
Accessory Auto-Detection
NI SC Express modules automatically detect compatible accessories or terminal blocks.
The RSVD pins on the I/O connector provide power to the accessories as well as digital
communication lines. This allows software to detect when accessories are inserted or removed.
In addition, software can automatically identify the specific terminal block as well as access any
calibration or scaling information associated with the terminal block.
Measurement & Automation Explorer (MAX) allows you to see the accessories connected to
your device. In MAX, expand Devices and Interfaces and locate your device. If a terminal block
is connected to your device, it will be displayed beneath the device. Unsupported terminal blocks
appear in MAX with an X next to them.
NI-DAQmx property nodes can be used to programmatically access information about
connected accessories in your application. Refer to the
NI-DAQmx Help
for documentation on
programmatically accessing accessory status. Select
Start»All Programs»National
Instruments»NI-DAQ»NI-DAQmx Help
.
Table 2-5.
ADC Conversion Rates
ADC Timing Modes
ADC Conversion Rate
1 (High Resolution)
*
1.1 Hz
2
1.8 Hz
3
2.3 Hz
4
11.9 Hz
5
14.2 Hz
6
35 Hz
7
68 Hz
8
196 Hz
9 (High Speed)
401 Hz
*
ADC timing mode 1 is the default setting for the On-Demand timing mode when the
ADC Timing
Mode
property is not explicitly selected.
ADC
Conv
Rate
Samp
Rate
max # of channels on any one ADC
(
)
[
]
×
=
