LI-8250 Multiplexer

Central to a LI-COR long-term system is the LI-8250 Multiplexer. The LI-8250 acts as a single point of access to interact with and control a LI-COR gas analyzer and up to 8 chambers.

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Where Precise Gas Analysis Meets Patented Chamber Technology

As the access point of communication, the LI-8250 lets you control, monitor, and review measurements from each chamber. When connected with a LI-COR gas analyzer, see live flux calculations and diagnostics at your site. Connect with a third-party analyzer to provide time-synchronization for post-processing of fluxes of other gases.

The LI-8250 includes an embedded Wi-Fi server. This server allows you to connect to the Multiplexer using any Wi-Fi enabled device via browser. Add a cellular modem to receive daily summary files and remotely monitor your system—visit the site only as necessary.

LI-8250

How is the LI-8250 Multiplexer different from the LI-8150 Multiplexer?

LI-8250 Multiplexer LI-8150 Multiplexer
Rugged and fieldable Checkmark Checkmark
Third-party analyzer integration Checkmark Checkmark
Custom chamber integration Checkmark Checkmark
SDI-12 compatible long-term chambers Checkmark
Built-in Wi-Fi connectivity* Checkmark
Real-time flux processing Checkmark
No separate analyzer control unit required Checkmark

* Wi-Fi connectivity limited in some countries
† When connected to a LI-COR gas analyzer

Preliminary Specifications

General

  • Dimensions: 38.5 cm L × 52 cm W × 18.5 cm H
  • Weight: 7.7 kg
  • Weatherproof Rating: Tested to IEC IP55 standard
  • Operating Range:
    • Temperature: –20 to 45 °C
    • Humidity: 0 to 95% RH, non-condensing
  • User Data Storage: 8 GB total non-volatile
  • GPS: Accuracy 2.5 m CEP
  • Coverage Area:
    • Maximum radius from LI-8250 to chambers: 15.0 m with one extension tube.
    • Maximum diameter of measurement circle: 30.0 m with one extension tube on each chamber.
  • Plumbing:
    • Flow rate to/from chambers: ~2 to 3 lpm
    • Pump type: Diaphragm (pumps in the analyzers subsample air stream in the LI-8250)
  • Barometric Pressure Sensor:
    • Measurement Range: 20 to 110 kPa
    • Sensor Accuracy: ±0.4 kPa from 50 to 110 kPa
    • Resolution: 0.006 kPa

Communication

  • Seven LED Indicators: Power, Ready, Ethernet activity (3), USB activity (2)
  • Connectivity: Three Ethernet Ports, Wi-Fi (not available in some countries)
  • Wi-Fi Compatibility: 2.4 GHz, 802.11 a/b/g/n/ac
  • Connectivity Ports:
    • USB-A: One sealed and strain-relieved for connection to LI-870 CO2/H2O Analyzer
    • USB-A: Two standard, internal for mass storage (file transfer) or a country specific Wi-Fi adapter.
    • RJ-45 Ethernet: Three sealed and strain-relieved for connection to LI-COR Trace Gas Analyzers, site Ethernet network, or cellular modem. Connectors also accept standard, non-sealed RJ-45 Ethernet cables for lab use.
  • Output Port Connector: RS-422 communication plus 24 VDC power, full duplex, 115,200 baud. +24 VDC output power is current limited to ~1.8 A per output port.

Power

  • Power Requirements: 10 to 30 VDC (120 VAC and 240 VAC with optional power supply). The LI-8250 powers the LI-870 when connected. Other analyzers are powered separately. See Table 1 for total system power requirements.

Table 1. Total system power requirements.

Typical Power Consumption (W)
Instrument Idle Sampling/ Moving Max/ Warm-up
LI-8250 4.8 15.6 18.2
8200-104 (each) 0.36 4.8 N/A
LI-870 5.0 5.0 14.0

Note: The max listed for the LI-8250 is a typical maximum, there is no additional warm-up power. Chamber power reaches 4.8 W only when opening or closing, not the entire time of sampling.

AC to DC Power Supply (8250-770)

  • Dimensions: 15 cm L × 12.5 cm W × 8.5 cm H
  • Weight: 1.3 kg
  • Weatherproof Rating: Tested to IEC IP55 standard
  • Environmental Operating Conditions: Tested to IP55 for dust and water ingress
  • Operating Temperature Range: –20 to 50 °C
  • Power Requirements: 100 to 240 VAC, 50/60 Hz, 120 VA
  • Output Voltage: 12 VDC, 6.67 A

Specifications subject to change without notice.

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