Appendix Kpar Sensor - YSI 6 series User Manual

PAR Sensor Appendix K
APPENDIX K PAR SENSOR
Some users of the YSI 6600-style sonde (6600V2-2, 6600EDS V2-2, and 6600V2-4) may wish to
incorporate a photosynthetically active radiation (PAR) sensor into their field monitoring equipment. This
sensor can be added to the 6600 in the form of a special product engineered by Endeco/YSI. This section is
designed to give potential users of this type of system an idea of how it is configured and the steps
necessary to acquire and log PAR data with the modified sonde.
Li-Cor PAR sensors are required for the 6600 modification and these can either be supplied to Endeco/YSI
by the user or can be purchased from Endeco/YSI as part of the system cost. These sensors are then
attached to "arms" which extend from the sonde and their output cables are connected to the sonde PCB
through the top of the sonde as shown in the following picture. The picture shows the installation of two
sensors (one pointing up, the other pointing down), but it is also possible to use a single PAR sensor if the
user prefers that configuration.
Each Li-Cor PAR sensor can be individually configured by Endeco/YSI with an internal circuit to have
variable sensitivities: high (usually employed for "upwell" or downward pointing sensors) or low (usually
employed for "downwell" or upward pointing sensors). After sensitivity configuration, the outputs of the
sensors are fed into the main sonde PCB thorough ISE ports ISE3 and ISE4. The ports can, in turn, be
configured in the Sensor and Report menus to show the presence of the PAR sensors (PAR1 for ISE3) and
PAR2 for ISE4), allowing the user to view or internally log their data during profiling or unattended
monitoring studies.
If the default settings of the sonde software are accepted, the PAR outputs will simply be in millivolts.
However, it is also possible to enter the calibration constants provided by Li-Cor into the sonde software
through the Advanced|Sensor menu. If these constants are entered then the units viewed or logged from
2
the PAR sensors will be shown as "Photosynthetic Photon Flux Density" with units of umoles/second/m .
A typical Certificate of Calibration as supplied by Li-Cor is shown below:
YSI Incorporated Environmental Monitoring Systems Operations Manual K-1