What is the highest resolution scan rate for the ATMOS 22 and ATMOS 41?
With the ATMOS 41 and the M command, using a non-METER data logger, you can make measurements every 3 seconds. With the ATMOS 22 and the M command, using a non-METER data logger, you can make measurements every 1 second. Consult the integrator guides for more information. Contact METER if your application requires more frequent measurements.
How frequently are measurements taken?
The ZL6 makes a measurement from each of the sensor ports in use every 60 s. However, the minimum measurement interval is five minutes for uploading data to ZENTRA Cloud. One-minute measurement interval is possible if you disable uploading data to ZENTRA Cloud, and these instructions are available upon request. The ATMOS 22 measures the wind speed and direction once every 10 s and records the instantaneous wind vector components. When queried, the ATMOS 22 outputs the average of the instantaneous measurements since the last query for wind speed and direction and the maximum instantaneous wind speed value for wind gust.
If using a non-METER logger, then the ATMOS 22 can be scanned every 1 second, but it is not necessary to oversample the ATMOS 22 and compute averages, accumulations, and maximums in external data systems because it has an internal measurement sequence [see the integrator guide for more information]. Less frequent sampling has the additional benefit of decreasing data acquisition systems and ATMOS 22 power consumption.
Can I install my ATMOS 22 at a 90 degree angle for vertical wind speed?
The ATMOS 22 should measure in any orientation if its measurement path is parallel to the wind flow. However, it should not be mounted at 90 degrees outside. This is due to rain obstructing the measurement during rain storms and possibly that water could be retained where the sonic transducers are, which would affect the measurement. Vertical wind speed outside is also associated with upward and downward eddies. These have both a horizontal and vertical component to them. If you mount an ATMOS 22 sideways, you would block the horizontal movement of these eddies and, presumably, negate any reason for doing it in the first place. The ATMOS 22 would be appropriate for measuring vertical wind velocity in certain indoor situations where the sensor is protected from pooling water and the wind vector is vertical (e.g., velocity in vertical HVAC ductwork).
What is the practical lower limit of the wind speed measurement for the ATMOS 22 and ATMOS 41?
The practical lower limit for wind speed is about 0.03 m/s for our sonic anemometer. This is much better than cup anemometers, for example, which struggle making measurements below 0.5 m/s at the minimum because of difficulty starting and stopping. Sonic anemometers can read five times lower than that, yet they don’t necessarily read absolute zero.
How do I assemble the anemometer mast?
The anemometer mast is suitable to mount METER’s above-ground sensors: ATMOS 41, ATMOS 22, ATMOS 14, PAR, PYR, IRT, SRS, PHYTOS 31, ECRN-100, ECRN-50, and ECT. For assembly, read: "Anemometer Mast Assembly Instructions."