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 36 chambers or flasks.
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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.
Reaching 36 Chambers
The LI-8250 Multiplexer has 8 ports. Each multiplexer port can connect to either a chamber or an 8250-01 Extension Manifold. You can have a maximum of 4 extension manifolds connected to the LI-8250 Multiplexer.
Each extension manifold also has 8 ports that can connect to chambers. Since the extension manifold uses 1 multiplexer port, each extension manifold gains you up to 7 more chambers.
With 4 extension manifolds, you can have 32 chambers on extension manifold ports and another 4 chambers on the remaining multiplexer ports.
Interested in measuring trace gas evolution in flasks? The 8250-660 Flask Sampling Kit enables you to use your long-term system for flask measurements too.
Read the Application NoteLI-8250 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 cable assembly or 30.0 m with an Extension Manifold and two cable assemblies.
- Maximum diameter of measurement circle: 30.0 m with two cable assemblies or 60.0 m with two Extension Manifolds and four cable assemblies.
- 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 8200-104/C chambers, the 8250-01 Extension Manifold, and the LI-870 CO2/H2O Analyzer.
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 |
| 8250-01 (each) | 0.8 | 9.2 | 11.0 |
| 8200-104/C (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
- Alternate Power Input: 21.9 to 26.5 VDC 80 W
Flask Sampling Kit (8250-660) Specifications
Power
- Power Requirements: Input voltage is supplied by the LI-8250 Multiplexer or the 8250-01 Extension Manifold. When a Purge Pump is configured to an Extension Manifold, the Extension Manifold must be connected to a power supply, such as the Indoor Power Supply (8250-772), via the Alternate Power Input. See Table 2 for 8250-660 power requirements.
Table 2. 8250-660 power requirements.
| Typical Power Consumption (W) | |||
|---|---|---|---|
| Instrument | Idle | Sampling/ Moving | Max/ Warm-up |
| 9982-079 Thermistor Input Module (each) | 0.12 | 0.12 | N/A |
| 9982-077 Purge Pump (each) | 5.8 | 5.8 | 7.0 |
| Flask Sampling Kit Total (each) | 5.92 | 5.92 | 7.12 |
Note: The power requirements for the 9982-077 Purge Pump are based on the pump being configured to run in the user interface. If the pump is not configured to run, it will use no power.
Thermistor
- Thermistor Input Module (9982-079)
- Operating Range: -20 to 70 °C
- Optional Thermistor Assembly (9982-081)
- Operating Range: -20 to 70 °C
- Accuracy: ±0.3 °C from -20 to 70 °C
Specifications subject to change without notice.
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