Chapter 3
Functional Details
Theory of operation - analog input acquisition modes
The
Maximum throughput is
Maximum throughput may be lower in Windows operating systems that predate Windows XP.
Software paced mode
In software paced mode, you can acquire one analog sample at a time. You initiate the A/D conversion by calling a software command. The analog value is converted to digital and returned to the computer. You can repeat this procedure until you have the total number of samples that you want from one channel.
The maximum throughput sample rate in software paced mode is
Continuous scan mode
In continuous scan mode, you can acquire data from up to eight channels. The analog data is continuously acquired and converted to digital values until you stop the scan. Data is transferred in blocks of 31 samples from the
The maximum continuous scan rate of 50 kS/s is an aggregate rate. The total acquisition rate for all channels cannot exceed 50 kS/s. You can acquire data from one channel at 50 kS/s, two channels at 25 kS/s, and four channels at 12.5 kS/s. You can start a continuous scan with either a software command or with an external hardware trigger event.
External components
The
USB connector
LED
Screw terminal banks (2)
Figure 3. OM-USB-1208FS external components
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