METER ATMOS 22 User Manual

ATMOS 22 INTEGRATOR GUIDE

SENSOR DESCRIPTION

The ATMOS22 Ultrasonic Anemometer is designed for continuous monitoring of wind speed and direction
(see Measurement Specifications). Ultra-low power consumption and a robust, no moving parts design that
prevents errors because of wear or fouling, make the ATMOS22 ideal for long-term, remote installations.

NOTE: The ATMOS22 replaces the DS-2 (discontinued) and the outputs and order are not the same as the DS-2. Any DS-2 replaced by
the ATMOS 22 will require data acquisition system reprogramming based on information located in the tech note Integrators replacing

DS-2 with ATMOS 22.

APPLICATIONS

• Weather monitoring

• Microenvironment monitoring

• In-canopy wind measurement

• Spatially distributed environmental monitoring

• Wind profiling

• Crop weather monitoring

• Fire danger monitoring/mapping

• Weather networks

18195-06

7.31.2020

ADVANTAGES

• Robust, no moving parts design

• Small form factor

• Low-input voltage requirements

• Low-power design supports battery-operated
dataloggers

• Supports the SDI-12 three-wire interface

• Tilt sensor informs user of out-of-level conditions

• No configuration necessary

PURPOSE OF THIS GUIDE

METER provides the information in this integrator
guide to help ATMOS22 Ultrasonic Anemometer
customers establish communication between these
sensors and their data acquisition equipment or
field data loggers. Customers using data loggers
that support SDI-12 sensor communications
should consult the data logger user manual. METER
sensors are fully integrated into the METER system
of plug-and-play sensors, cellular-enabled data
loggers, and data analysis software.

COMPATIBLE FIRMWARE VERSIONS

This guide is compatible with firmware versions 1.07 or newer.

Figure 1 ATMOS22 Ultrasonic Anemometer

METER Group, Inc. USA

2365 NE Hopkins Court, Pullman, WA 99163

T +1.509.332.2756 F +1.509.332.5158
E [e-mail] W metergroup.com

SPECIFICATIONS

MEASUREMENT SPECIFICATIONS

Horizontal Wind Speed

Range 0 –30 m/s

Resolution 0.01 m/s

Accuracy The greater of 0.3 m/s or 3%

of measurement

Wind Gust

Range 0 –30 m/s

Resolution 0.01 m/s

Accuracy The greater of 0.3 m/s or 3%

of measurement

COMMUNICATION SPECIFICATIONS

Output

SDI-12 communication

PHYSICAL SPECIFICATIONS

Dimensions

Diameter 10 cm (3.94 in)

Height 16 cm (6.30 in), includes rain

gauge filter

Operating Temperature Range

Minimum –50 °C

Typical NA

Maximum 60 °C

Wind Direction

Range 0° –359°

Resolution 1°

Accuracy ±5°

Tilt

Range –90° to 90°

Resolution 0.1°

Accuracy ±1°

Data Logger Compatibility

METER ZL6, Em50, and EM60 data loggers or
any data acquisition systems capable of 3.6- to

15.0-VDC excitation and SDI-12 communication

Cable Length

5 m (standard)
75 m (maximum custom cable length)

NOTE: Contact Customer Support if nonstandard cable length
is needed.

Connector Types

3.5-mm stereo plug connector or stripped and
tinned wires

ELECTRICAL AND TIMING CHARACTERISTICS

Supply Voltage (VCC to GND)

Minimum 3.6 VDC continuous

Typical NA

Maximum 15.0 VDC continuous

NOTE: The ATMOS 22 must be continuously powered to
workproperly.

NOTE: For the ATMOS 22 to meet digital logic levels specified
by SDI-12, it must be excited to 3.9 VDC or greater.

Digital Input Voltage (logic high)

Minimum 2.8 V

Typical 3.6 V

Maximum 5.0 V

Digital Input Voltage (logic low)

Minimum –0.3 V

Typical 0.0 V

Maximum 0.8 V

Digital Output Voltage (logic high)

Minimum NA

Typical 3.6 V

Maximum NA

NOTE: For the ATMOS 22 to meet digital logic levels specified
by SDI-12, it must be excited to 3.9 VDC or greater.

Power Line Slew Rate

Minimum 1.0 V/ms

Typical NA

Maximum NA

2

Power (brown)

GND

Current Drain (during measurement)

Minimum 0.2 mA

Typical 8.0 mA

Maximum 33.0 mA

Power Up Time (SDI-12, DDI disabled)

Minimum NA

Typical 200 ms

Maximum NA

Current Drain (while asleep)

Minimum 0.2 mA

Typical 0.3 mA

Maximum 0.4 mA

Power Up Time (SDI ready)—aRx! Commands

Minimum NA

Typical 10 s

Maximum NA

Power Up Time (SDI ready)—Other Commands

Minimum NA

Typical 130 ms

Maximum NA

Measurement Duration

Minimum NA

Typical 110 ms

Maximum 3,000 ms

COMPLIANCE

Manufactured under ISO 9001:2015

EM ISO/IEC 17050:2010 (CE Mark)

EQUIVALENT CIRCUIT AND CONNECTION TYPES

Refer to Figure 2 and Figure 3 to connect the ATMOS22 to a logger. Figure 2 provides a low-impedance variant
of the recommended SDI-12 Specification v1.3.

PIGTAIL CABLE

GND

DATA

Ground (bare)

Digital
communication (orange)

R1

510

NOTE: Some early ATMOS22 units may have the older Decagon
wiring scheme where the power supply is white, the digital out is red,
and the bare wire is ground.

STEREO CABLE

R2

Figure 2 Equivalent circuit diagram

C1

100K

220PF

Figure 3 Connection types

Ground
Digital communication
Power

SAFETY PRECAUTIONS

METER sensors are built to the highest standards, but misuse, improper protection, or improper installation
may damage the sensor and possibly void the warranty. Before integrating sensors into a sensor network,
followthe recommended installation instructions and implement safeguards to protect the sensor from
damaging interference.

SURGE CONDITIONS

Sensors have built-in circuitry that protects them against common surge conditions. Installations in
lightning-prone areas, however, require special precautions, especially when sensors are connected to a
well-grounded third-party logger.

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CABLES

Improperly protected cables can lead to severed cables or disconnected sensors. Cabling issues can be
caused by many factors, including rodent damage, driving over sensor cables, tripping over the cable, not
leaving enough cable slack during installation, or poor sensor wiring connections. To relieve strain on the
connections and prevent loose cabling from being inadvertently snagged, gather and secure the cable
traveling between the ATMOS 22 and the data acquisition device to the mounting mast in one or more places.
Install cables in conduit or plastic cladding when near the ground to avoid rodent damage. Tie excess cable to
the data logger mast to ensure cable weight does not cause sensor to unplug.

SENSOR COMMUNICATIONS

METER digital sensors feature a 3-wire interface following SDI-12 protocol for communicating
sensor measurements.

SDI12 INTRODUCTION

SDI-12 is a standards-based protocol for interfacing sensors to data loggers and data acquisition equipment.
Multiple sensors with unique addresses can share a common 3-wire bus (power, ground, and data). Two-way
communication between the sensor and logger is possible by sharing the data line for transmit and receive
as defined by the standard. Sensor measurements are triggered by protocol command. The SDI-12 protocol
requires a unique alphanumeric sensor address for each sensor on the bus so that a data logger can send
commands to and receive readings from specific sensors.

Download the SDI-12 Specification v1.3 to learn more about the SDI-12 protocol.

DDI SERIAL INTRODUCTION

The DDI serial protocol is the method used by the METER family of data loggers for collecting data from
the sensor. This protocol uses the data line configured to transmit data from the sensor to the receiver only
(simplex). Typically, the receive side is a microprocessor UART or a general-purpose IO pin using a bitbang
method to receive data. Sensor measurements are triggered by applying power to the sensor. When the
ATMOS22 is set to address 0, a DDI serial string is sent on power up, identifying the sensor.

INTERFACING THE SENSOR TO A COMPUTER

The serial signals and protocols supported by the sensor require some type of interface hardware to be
compatible with the serial port found on most computers (or USB-to-serial adapters). There are several
SDI-12 interface adapters available in the marketplace; however, METER has not tested any of these
interfaces and cannot make a recommendation as to which adapters work with METER sensors. METER data
loggers and the ZSC and PROCHECK handheld devices can operate as a computer-to-sensor interface for
making on-demand sensor measurements. For more information, please contact NORTH AMERICA.

METER SDI12 IMPLEMENTATION

METER sensors use a low-impedance variant of the SDI-12 standard sensor circuit (Figure 2). During the
power-up time, sensors output some sensor diagnostic information and should not be communicated with
until the power-up time has passed. After the power up time, the sensors are compatible with all commands
listed in the SDI-12 Specification v1.3 except for the continuous measurement commands (aR0–aR9 and aRC0–
aRC9). M, R, and C command implementations are found on page 7.

Out of the factory, all METER sensors start with SDI-12 address 0 and print out the DDI serial startup string
during the power-up time. This can be interpreted by non-METER SDI-12 sensors as a pseudo-break condition
followed by a random series of bits.

The ATMOS22 will omit the DDI serial startup string (sensor identification) when the SDI-12 address is nonzero.
Changing the address to a nonzero address is recommended for this reason.

ATMOS22 INTERNAL MEASUREMENT SEQUENCE

Upon power up, the ATMOS 22 initializes an internal timer to 55. This internal timer is incremented by 1 every
second and resets to 0 after incrementing to 59. In addition, issuing an averaging command (aM!, aR0!, aR3!,
and aC!) resets this timer to 55.

While powered up, the ATMOS 22 takes wind and air temperature measurements every 10 s at internal timer
intervals of 0, 10, 20, 30, 40, 50 and logs these values internally. Orientation is measured every 60 s at the
internal timer interval of 4 and logged internally. The aR4! command will output instantaneous measurements
of theseparameters.

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