Overview of the LI-8150 multiplexer

The LI-8150 Multiplexer is an accessory for the LI-8100A that makes it possible to connect as many as 16 long-term chambers. Data from this configuration is useful for characterizing spatial and temporal variation of soil gas flux. The LI-8150 can also be connected to ordinary gas sampling lines for vertical profiling, custom chambers, or other studies.

Figure 4‑1. The LI-8150 Multiplexer supports up to 16 chambers, with a measurement diameter of up to 30 meters.

What's what

If you have just taken delivery of your LI-8150 check the packing list to verify that you received everything ordered, including the following items:

Cable and tube assembly

Contains one cable and two tubes for connecting the LI-8100A Analyzer Control Unit to the LI-8150 Multiplexer.

Power cable

The power cable (part number 8150-706) is a 3 m cable with bare wire leads for connection to a user-supplied DC power source (10.5-14.5 VDC). The red lead connects to a positive terminal; the black lead connects to a negative terminal.

Spare parts kit

This box contains replacement parts for your LI-8150. As you become familiar with the system you will learn which items to keep close at hand and which items can be stored away. Additional spares kits are packaged with the soil chambers, as well.

The spares kits include these commonly used items:

Description Qty. LI-COR Part No.
Multiplexer Spares Kit 1 9981-130
Urethane Tubing, 1/8” ID x 11” OD 3 ft. 222-00303
Hose Barb T-Fitting 2 300-02627
11” Quick Connect Plug 2 300-08151
3 Amp 250 V Fuse 1 439-04215
4 Amp 250 V Fuse 1 439-08516
Jumper Tube Assembly 1 9981-142
Filter Replacement Kit (set of 8) 1 or 21 8150-909

Optional accessories

Optional accessories may be provided, depending on the configuration you ordered.

AC to DC power supply

When used with the multiplexer, the AC to DC power supply (part number 8150-770) provides power to both the multiplexer and the LI-8100A. The power supply provides a constant 12 VDC source (4.5 A maximum) to the multiplexer and LI-8100A. It is weather resistant, O-ring sealed, and is designed for long-term outdoor deployment. It has a user-selectable input voltage range of 115-120 or 230-240 VAC.

Cable and tube extension

The extensions (part number 8150-705) are used to place the chamber up to 15 meters from the multiplexer.

NOTE: Only one extension is recommended for each chamber. Contact technical support for more information about longer tube and cable runs.

Soil moisture probes

The 8150-202 ECH2O Model EC-5 soil moisture probe (Decagon Devices, Inc., Pullman, WA) is a 5 cm (2") dielectric sensor that measures volumetric water content of the soil. The 8150-202 probe has a plug for direct connection to the 8100-104/C Long Term chambers.

The 8150-204 ThetaProbe has a connector pre-installed for direct connection to the 8100-104/C soil chambers.

Soil temperature thermistor

Part number 8150-203 has a 2 m (6') cable. It connects to the 8100-104/C Long-Term Chamber. Accuracy: ±1.0 °C from –20 to 50 °C.