Advantech USB-5820, Руководство пользователя

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USB-5820 User Manual 22
3.6 Analog Output Update Rate
The maximum update rate of the DACs in USB-5820 is 200 kS/s, and this update
rate is shared by all enabled channels. For example, if only one AO channel is
enabled, the maximum update rate of the output signal is 200 kS/s. On the other
hand, if all four AO channels are enabled, the maximum update rate for each channel
decreases to 50 kS/s (200 kS/s divided by 4). The aggregate update rate is still 200
kS/s.
The actual update rate, however, may differ from the configured value by a small
amount. The update clock for the DACs is generated from dividing an internal 66.666
MHz clock by an integer value divisor. To calculate the divisor, one needs to divide
the 66.666 MHz by the desired aggregate update rate. For example, if all 4 AO chan-
nels are enabled and the update rate is 50 kS/s, the aggregate update rate is 200 kS/
s (50 kS/s multiplied by 4), and the divisor is calculated as
The actual aggregate update rate can be calculated as:
And actual update rate of each channel is:
The divisor range is between 333 and 4,294,967,295 (2
32
- 1), and the actual aggre-
gate update rate is between 200.2 kHz and 0.01552 Hz.
3.7 Analog Output Triggering
The USB-5820 only supports software trigger.