Connecting an LI-78xx Trace Gas Analyzer

Part numbers: LI-8250,
LI‑78xx, and 9982‑011

The components you will need to make this connection are the LI-8250 Multiplexer (part number LI-8250), an LI-78xx Trace Gas Analyzer, and the LI-78xx Trace Gas Analyzer cable assembly (part number 9982-011).

This section will provide you with what you need to know to connect a LI-78xx Trace Gas Analyzer to your LI-8250 Multiplexer. Instructions for configuring a measurement are detailed in An overview of configurations.

Caution: LI-COR LI-78xx Trace Gas Analyzers are water-resistant, but they are not waterproof. They should not be allowed to sit in standing water, be directly exposed to driving rain, or be deployed outdoors without weather protection.

Network cable connector

The LI-8250 communicates with LI-78xx Trace Gas Analyzers using an RJ-45 Ethernet cable. This cable is part of the LI-78xx Trace Gas Analyzer cable assembly (part number 9982-011). The cable assembly must be ordered separately.

Note: Only use the supplied 2 m Cat5e RJ-45 Ethernet cable from the LI-78xx Trace Gas Analyzer cable assembly (part number 9982-011).

Making the connection

Connecting the LI-8250 Multiplexer and an LI-78xx Trace Gas Analyzer takes just a few steps.

Note: The LI-8250 Multiplexer air out to Trace Gas Analyzer air in tubing is distinguished on each end with black plastic shrink wrap. Take care to ensure this tubing and your assembled connectors are installed to the AIR OUT port of the LI-8250 Multiplexer and the IN port on the Trace Gas Analyzer. Mixing up the connection will cause incorrect mixing and unexpected results in your data.

LI-78xx Trace Gas Analyzers use a 1/4"compression fitting for tubing at both the air in and air out ports.

The LI-78xx Trace Gas Analyzer cable assembly comes pre-assembled with a knurled nut (part number 300-05896), stainless steel insert (part number 300-18126), and stainless steel ferrule (part number 300-15024) at one end to connect to the analyzer.

Thread the nut onto the compression fitting of your analyzer until finger tight and tighten the nut an additional 1/4 turn to ensure a good seal. Then connect the RJ-45 Ethernet cable to the Ethernet port of the Trace Gas Analyzer.

Complete the connection by connecting the air tubing and RJ-45 Ethernet connector to the multiplexer. Any available Ethernet port will work.

Note: For a fully seated and sealed connection, ensure the clips above and below the Ethernet connector have locked over the connector.