FM-120
Fog Monitor
This optical spectrometer continuously samples droplet-laden ambient air and produces size distributions in the range from 2 µm to 50 µm.
TALK TO AN EXPERTRely on the only all-weather ground-based instrument capable of measuring particle size distributions (PSDs) in the 2 µm to 50 µm size range – critical for understanding the evolution of fog, and useful for calculating number concentration, liquid water content, and extinction/visibility.
Get high-resolution information on particle light-scattering intensity with the PBP optional feature. This allows much more precise and detailed size distributions, as well as minimization of the well-known Mie scattering ambiguities.
Access raw data for one particle in each sampling instance. Use this information as an important instrument diagnostic.
Depend on automatic correction for drifts in polarization signals through the dynamic thresholding feature.
PADS – Particle Analysis and Display System
The FM-120 utilizes PADS to provide a user-friendly virtual instrument panel. PADS allows the user to control the FM-120 and display real-time data and logs. For instance, the program enables the user to do the following tasks:
- Sample and record data
- View particle volume and number concentrations, as well as Median Volume Diameter (MVD) and Effective Diameter (ED)
- View LWC as measured by the FM-120
- Monitor laser health and temperatures at various instrument locations
- Play back data for post-flight viewing
- Reprocess data with new parameters for additional analysis
Particle light-scattering
- The FM-120 is a forward-scattering optical spectrometer that accepts and sizes only particles that pass through a region of the laser beam with uniform power.
- Forward-scattered light is collected, directed through a 50/50 optical beam splitter, then measured by photodetectors to determine size and depth of field.
| Parameter | Specification |
|---|---|
| Measured Parameters | Single-particle forward light scattering |
| Auxiliary Parameters | Temperature Pressure |
| Derived Parameters | Particle diameter Particle number concentration Liquid water content (LWC) Effective diameter (ED) Median volume diameter (MVD) |
| Particle Size Range | Droplets with 2-50 µm diameter |
| Number of Size Bins | 30 |
| Typical Sample Area | 0.24 mm² |
| Sample Flow Volume | 1 m3/min |
| Sampling Frequency | Standard Data Rate: Selectable, 0.04 sec to 20 sec PBP Data Rate: No limit until particles are coincident |
| Refractive Index | Non-absorbing, 1.33 (the industry standard for water) |
| Light Collection Angles | ~3.5º - 12º |
| Data System Interface | RS-422 serial interface up to 460 kB |
| Environmental Operating Conditions | Temperature: -40 to 40 °C Relative Humidity: 0 - 100%, non-condensing Altitude: 0 - 4,000 meters |
| Weight | 18.5 kg (instrument), 13.0 kg (pump & hose) |
| Probe Dimensions | 23 cm H x 28 cm W x 37 cm L |
| Power Requirements | Universal input for analyzer head, 50-60 Hz 115-120V or 230V for pump (set at factory, but user-configurable) 200W (instrument), 400W (pump) |
The FM-120 can be purchased with a swivel-head mount. The swivel head ensures the instrument inlet is always facing into the wind.
The Lifecycle Care Program ensures FM-120 integrity and performance vital to your research mission for 3 years or 3 calls (whichever comes first). When conducting complex and time intensive laboratory or field measurements it is critical to avoid down time, and ensure data collection accuracy. The program consists of 3 key deliverables for each year or call:
- Instrument Logistics
- Instrument Integrity
- Instrument Performance
Lifecycle Care Program Includes:
LOGISTICS
- Shipping to and from Droplet Measurement Technologies facility
- Customs handling, including CARNET ATA if required
INTEGRITY
- Incoming instrument evaluation and health check
PERFORMANCE
- Software and firmware validation
- 100%-unit functionality test
- Calibration data
- Calibration report
- Certificate of calibration
At times, our technician might discover an instrument issue, which might not be covered by the Lifecycle Care Program or by our product warranty. In such case we will reach out to you with a service & repair estimate to allow you to provide us with the next steps of action.
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