2-11
Notes:
The ADC acquires data at a maximum of 40 kHz (one sample
every 25
µ
s). If you are using a hardware external clock, make sure that
the clock does not initiate conversions at a faster rate than the ADC
can handle.
To achieve full measurement accuracy when using a gain of 500, you
should limit the conversion frequency to a maximum of 25 kHz (one
sample every 40
µ
s).
If you are acquiring samples from multiple channels, the maximum
sampling rate for each channel is equal to 40 kHz divided by the number
of channels.
The rate at which the computer can reliably read data from the board
depends on a number of factors, including your computer, the operating
system/environment, whether you are using expansion boards, the gains
of the channels, and software issues.
You can synchronize conversions on multiple DAS-800 Series boards to a
common, externally applied conversion clock. In addition, you can use a
DAS-801 or DAS-802 board as a timing master; the output of the OUT1
pin (pin 5) on the main I/O connector of the master board acts as an
external hardware conversion clock to any additional boards. You can use
external circuitry, such as C/T0 on the 8254, to divide the rate of the
master clock; this allows you to synchronize conversions on the
additional boards to a rate different from that of the master board. Refer
to page 4-13 for more information on synchronizing conversions on
multiple boards.