Aerodyne 1

Aerodyne 2


The LGR instrument is an Off-Axis Laser Spectrometer that is used to measure the isotopic composition of liquid water and water vapor samples from both Prenart Lysimetric samples and hill-slope seepage samples. Seepage sample is collected from each hill-slope using a peristaltic pump. A LEAP Technologies Autoinjector is used to inject liquid water samples into the laser spectrometer. 

Valco Selector Valves

In total there are 31 primary Valco selector valves - 9 per landscape, for a total of 27 level-2 valves, 3 level-1 valves inside the isotope lab for selecting a single level-2 valve, and one for the isotope standard generation system.

Position Assignments

Positions as follows...

Valco Selector Control & Software

All 31 selector valves are controlled by a National Instruments Compact Reconfigurable Input/Output Real Time Controller (cRIO) utilizing RS232/RS485 communications bus. Each Valco is configured with a semi-unique address (unique to it's physical bus).

Calibration Sample Preparation System

To aid in data quality assurance we have developed a system for creating samples.


Temperature is controlled by providing a solid state relay with a 1 second (period) pulse width modulated signal in order to provide the desired average power delivery. The PWM signal is generated using an NI-9472 digital output module within a Compact RIO chassis.

PID & Logic

Each control loop is set to require a minimum amount of flow and a maximum allowable temperature.

HeaterCutoffMinimum FlowKcTiTd

Aerodyne 1 - Water Detection in Sample Lines

In order to prevent liquid water from reaching the Alicat flow controller and Aerodyne analyzer we have created a system which will stop flow by powering off the Alicat flow controllers upon successful detection of liquid water. This system consists of 6 major components:
1) IR based detector (Balluff BOH TJ-T)
2) Signal amplifier (Balluf MicroMote BAE00)
3) RT Controller (NI-9074)
4) Digital input module (NI-9425)
5) Digital output module (NI-9472)
6) Mechanical relay, 24V

The basis of this design is to cut power to the Alicat Power Distribution Unit (PDU) upon detection of liquid water.
The RT controller has FPGA software installed to disable the output of CH7 of the digital output module, which in turn disengages the mechanical relay, upon an input signal on CH0 of the digital input module.


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