Keithley KUSB-3100, User Manual

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Principles of Operation
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• External clock – An external clock is useful when you want to
pace acquisitions at rates not available with the internal clock or
when you want to pace at uneven intervals. The minimum
frequency of the external clock can be less than 30 Hz; the
maximum frequency of the external clock is 50 kHz.
Connect an external clock to the Ext Clock In signal on the
KUSB-3100 module. Conversions start on the rising edge of the
external clock input signal.
Using software, specify the clock source as external. The clock
frequency is always equal to the frequency of the external sample
clock input signal that you connect to the module.
Analog Input Conversion Modes
The KUSB-3100 module supports the following conversion modes:
• Single-value operations, described on this page.
• Continuous scan operations, described on page 12 .
Single-Value Operations
Single-value operations are the simplest to use. Using software, you
specify the range, gain, and analog input channel. The module
acquires the data from the specified channel and returns the data
immediately. For a single-value operation, you cannot specify a clock
source, trigger source, scan mode, or buffer.
Single-value operations stop automatically when finished; you
cannot stop a single-value operation.