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Tag: LI-840A

Troubleshooting RS-232 Connectivity Issues for LI-COR Analyzers

Troubleshooting RS-232 Connectivity Issues for LI-COR Analyzers

Many LI-COR gas analyzers feature RS-232 communication ports, and sometimes these are the only communication channels available between the gas analyzer and a computer. Many new computers don’t have built-in serial ports, so USB-to-serial adapters are needed to facilitate this communication process. Communication problems between gas analyzer and windows interface software can happen due to issues with the USB to serial adapter or due to the lack of compatibility between the instrument firmware version and the windows interface software version. Terminal…

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Temporary Fix for a Bad IR Source

Temporary Fix for a Bad IR Source

The infrared (IR) source for the LI-8xx series analyzers has an operational life of better than 20,000 hours, or about two years of continuous use. The IR source is essentially an incandescent light bulb, and fails as a result of the filament thinning with use as it burns away. Eventually the filament becomes thin enough that it cracks and breaks, at which point the source no longer works.

The permanent fix for a failed source is to replace it with…

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LI-820, LI-840/A, LI-8100/A, and terrible, horrible, no good, very bad data

LI-820, LI-840/A, LI-8100/A, and terrible, horrible, no good, very bad data

There are four common causes for bad readings on LI-8xxx instruments:

  1. Incorrect zero and span calibration parameters.
  2. IR light source that is failing or has failed.
  3. Contamination (dirt, corrosion, liquids) in the optical path.
  4. Failed detector.

1)  Incorrect zero and span calibration parameters:

Check these values using the LI-COR interface software for each instrument by going to:

For LI-820 and LI-840, LI-840A: View – Calibration – Advanced

For the LI-8100, LI-8100A: Utilities…

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