Anemometer

General Information

Instrument: 3 Axis Ultrasonic Anemometer 1590-PK-020/w with 4 14-bit analog outputs

Current Device Status (12/2/2021)

Analog output settings are configured to read out U, V, W, and sonic temperature at 32 Hz with an output range of 0-5 V. For U, V, W, this range has been set to correspond to -5 to +5 m/s and for temperature this range corresponds to -40 to 70 degrees C.

Analog outputs are then connected to the T7:
U - channel 1 - AIN0
V - channel 2 - AIN1
W - channel 3 - AIN2
sonic speed - channel 4 - AIN3

Sample Dataset taken over 10 min:

And zoomed in to ~half a second of data taking:

Relevant code for analyzing binary datafile

# -*- coding: utf-8 -*-
"""
Created on Tue Nov 30 02:11:06 2021

@author: brodi
"""

import pandas as pd
from sqlalchemy import create_engine

def load_pd(db_fi: str, table: str) -> pd.DataFrame:
    """
    loads pandas df from db given table name
    """
    engine = create_engine(db_fi, echo = False)
    with engine.connect() as sqlite_connection:
        df = pd.read_sql(table, sqlite_connection)
        
    return df

If database file is named anemometer, for instance, you can load it into a dataframe and then convert the relevant voltage measurements into wind speed and temperature with:

# Load datafile into pandas data frame
db_fi = r"sqlite:///anemometer.db"
df = load_pd(df_fi, "anem")

# Add columns in correct units
# because the units are +/- 5 m/s, 0 to 5 V
df['vx_ms'] = (df.vx - 2.5) * 2
df['vy_ms'] = (df.vy - 2.5) * 2
df['vz_ms'] = (df.vz - 2.5) * 2

# because sonic temperature is measured on a scale of 0 to 5 V
# from -40 to 70 C
df['tsonic'] = -40 + df.vsonic/5 * 110

#Plot data
plt.plot(df.t, df.vx_ms, label = 'Vx')
plt.plot(df.t, df.vy_ms, label = 'Vy')
plt.plot(df.t, df.vz_ms, label = 'Vz')
# plt.plot(df.t, df.tsonic/8 - np.mean(df.tsonic/8), label = 'Temp')

plt.legend()
plt.xlabel('Time')
plt.ylabel('Wind Speed (m/s)')
plt.show()

plt.plot(df.t, df.tsonic)
plt.xlabel('Time')
plt.ylabel(r'Sonic Temperature ($^o$C)')
plt.show()

Which gives the first plots in the previous section.

Relevant pin connections (all of which are copied from the manual)

Output pins from the anemometer (p. 15 of manual):

To change the analog output settings, connect a RS 432 serial port to a windows computer and to the anemometer outputs.

RS 432 serial port pin connections (p.32 of manual):

For the serial connector we were using, pin 2 was white, pin 3 was yellow, pin 5 was orange, but apparently this isn't necessarily generically true.

The windows computer should have WIND software downloaded on it. Follow p. 46 of the manual.

Mounting plate

through bolts are McMaster Carr

91770A868

Super-cheap hot-wire anemometer for airflow in the dome:

https://moderndevice.com/product/wind-sensor/

Ordered 10 of these. Be sure to use the RV output pin! Requires 5V supply, clean.

Downside is that the output voltage is a combination of temperature and wind speed. But a separate temperature output is provided, so we should be able to calibrate. dV/d(speed) is also depends on temperature.

Dimensions 0.68 × 1.59 × .125 in

Link to Github example code for temperature compensation: https://github.com/moderndevice/Wind_Sensor/blob/master/WindSensor/WindSensor.ino

We just need to calibrate this with a 2-d fit of RV output as a function of both windspeed and temperature. Not a big deal.

This can be mounted into an 18mm ID carbon tube, 20mm OD. Ordered that from Amazon, Jan 15 2022.

Clamps to hold this essentially 3/4" OD tubing: https://www.amazon.com/LAMPHUS-Off-Road-Vertical-Mounting-Aluminum/dp/B07FT2KVNL/ref=sr_1_3?crid=1NO43HYA9LQWW&keywords=3%2F4%22+clamp+mount+bracket+bull+bar&qid=1642262996&sprefix=3%2F4+clamp+mount+bracket+bull+bar%2Caps%2C86&sr=8-3&qty=10

also ordered Jan 15, 2022 from Amazon.

We can use an array of these in the dome to measure scalar wind speed field. Need to calibrate signal vs. theta, phi for these sensors, but we should pretty much know the direction of the prevailing wind- through the slit and out the vents.

Ordered 100 feet of 4-pair cable from Digikey- 2467CSL005-ND‎

References

Re-Visiting Acoustic Sounding to Advance the Measurement of Optic.pdf