Sequoia LISST-100X, Руководство пользователя

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LISST-100X User’s Guide 5
Depth and
Temperature In addition to measuring the particle size and concentration, the
LISST-100X also has built-in Depth and Temperature sensors.
The Depth sensor is a 500 psi strain gauge sensor
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. The stainless
steel fitting on the Connector endcap is used for testing this sensor.
It is not required for normal operation. However, when not used for
testing, this fitting helps keep contamination such as salt and
sediment out of the pressure sensor. The temperature is
measured using a high precision thermistor imbedded into the
Connector end cap. Both values are stored automatically in the
standard-format LISST-100X data file.
Note that because the temperature sensor is embedded in the
endcap, it has a significant lag as the entire connector endcap
must respond to the changing temperature. The temperature
sensor will work well if the rate of change is slow, e.g. a front
moving past the instrument, but it will show a significant lag if the
rate of change is large, such as typically happens during profiling
applications.
External I/O
Ports
The LISST-100X is also equipped with an external ANALOG IN
port for recording the output of one other analog instrument.
Additionally, 2 DIGITAL I/O ports are provided for communicating
with up to two instruments. The I/O ports can be used for
synchronization of the LISST-100X with two other instruments; e.g.,
the LISST-100X may provide a timing pulse to a CTD, or it may
provide a 'start sample' pulse to another LISST-100X. The same
ports can be used to receive similar commands. Contact Sequoia
Scientific for more information on interfacing the LISST-100X with
other instruments. These ports are available on the 6-pin
underwater connector on the Connector end cap; see Appendix C:
Connector Pinouts for LISST-100X for the connector pin outs. The
instrument can be configured to use the Digital I/O ports as a
trigger to start and stop sampling.
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A gauge pressure sensor is calibrated to measure the pressure relative to a given atmospheric pressure, as opposed to
an absolute pressure sensor, which measures pressure relative to a vacuum. The pressure sensor on the LISST-100X
will read 0 at atmospheric pressure.