Meilhaus Electronic redlab 1208fs, Руководство пользователя

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RedLab 1208FS User's Guide Functional Details
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ƒ Configure as an external clock input to externally source the A/D conversions. The SYNC terminal
supports TTL-level input signals of up to 50 kHz.
ƒ Configure as an output to synchronize with a second USB unit and acquire data from 16 channels.
Refer to the pinout diagrams on page 16 for the location of this pin. For more information on synchronizing
multiple units, refer to page 25.
Counter terminal
The
CTR
connection (pin 20) is input to the 32-bit external event. Refer to the pinout diagrams on page 16 for
the location of this pin. The internal counter increments when the TTL levels transition from low to high. The
counter can count frequencies of up to 1 MHz.
Accuracy
The overall accuracy of any instrument is limited by the error components within the system. Quite often,
resolution is incorrectly used to quantify the performance of a measurement product. While "12-bits" or "1 part
in 4096" does indicate what can be resolved, it provides little insight into the quality of an absolute
measurement. Accuracy specifications describe the actual results that can be realized with a measurement
device.
There are three types of errors which affect the accuracy of a measurement system:
ƒ offset
ƒ gain
ƒ nonlinearity.
The primary error sources in the RedLab 1208FS are offset and gain. Nonlinearity is small in the RedLab
1208FS, and is not significant as an error source with respect to offset and gain.
Figure 11 shows an ideal, error-free, RedLab 1208FS transfer function. The typical calibrated accuracy of the
RedLab 1208FS is range-dependent, as explained in the "
Specifications " chapter on page 27. We use a ±10 V
range here as an example of what you can expect when performing a measurement in this range.
-FS
+ FS
Input Voltage
0
4095
Output Code
2048
Figure 11. Ideal ADC transfer function