data is calculated by collecting 128 samples and evaluating the standard deviation (RMS noise).
n is the noise-free resolution, and is the resolution obtained by all
d
of
ut the values from those bits should be
nored. The timers/counters (200-224) must be configured before streaming using normal
timer/counter configuration commands.
The timing for these special channels is the same as for normal analog channels. For instance,
a stream of the scan list {0,1,200,224,201,224} counts as 6 channels, and the maximum scan
rate is determined by taking the maximum sample rate at the specified resolution and dividing
by 6.
n streaming timers configured in mode 2 or 3 (32-bit period
easurement). It is possible for the LSW to roll, but the MSW be captured before it is
,
The second ENOB colum
readings. This data is calculated by collecting 128 samples and evaluating the maximum value
minus the minimum value (peak-to-peak noise). Similarly, the Noise Counts column is the
peak-to-peak noise based on counts from a 12-bit reading.
Interchannel delay is the time between successive channels within a stream scan.
3.2.1 Streaming Digital Inputs, Timers, and Counter0
There are special channel numbers that allow digital inputs, timers, and counters, to be
streamed in with analog input data.
Channel#
193 EIO_FIO
200 Timer0
201 Timer1
210 Counter0
211 Counter1
224 TC_Capture
Table 3-5. Special Stream Channels
Channel number 193 returns the input states of 16 bits of digital I/O. FIO is the lower 8 bits an
EIO is the upper 8 bits.
Channels 200-201 and 210-211 retrieve the least significant word (LSW, lower 2 bytes) of the
specified timer/counter. At the same time, the most significant word (MSW, upper 2 bytes) is
stored in an internal timer/counter capture register (TC_Capture), so that the proper value can
e sampled later in the scan.
b
Adding these special channels to the stream scan list does not configure those inputs. If any
the FIO or EIO lines have been configured as outputs, timers, counter, or analog inputs, a
hannel 193 read will still be performed without error b
c
ig
Special care must be taken whe
m
incremented. If this is an unacceptable situation, then only the LSW or MSW should be used
but not both.
43
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