Vaisala WAC155 Technical data
Vaisala Instruments Catalog 2009
Ref. B210768EN rev. A
WAC155 Serial Wind Transmitter
e WAC155 is designed to communicate the wind speed and direction data measured
over the RS-485 serial bus.
P.O. Box 26, FI-00421 Helsinki, FINLAND
Tel: +358 9 894 91
Fax: +358 9 8949 2485
Email: industrialsales@vaisala.com
www.vaisala.com/WAC155
Features/Benefits
• Capable of measuring the wind
parameters at a congurable
interval (typical 3 seconds) using
the instant method according to
the WMO standard
• Communication with the host
system with NMEA 0183 compliant
protocol over RS-485 electrical
interface (half-duplex)
• Fail-safe RS-485 operation with
congurable baud rate and
turnaround delay
• Congurable ID setting
• Adjustable heating control of sensors
• Auto-detection of sensor failure
e Vaisala Serial Wind Transmitter
WAC155 converts the digital data
supplied by the Vaisala WA15 and
WA25 Series wind sensors for use
in the RS-485 bus. e electrical
connections to the sensors are 6-bit
parallel graycode for the direction
measurement and up to 750Hz digital
pulse for the wind speed measurement
(anemometer) . e WAC155 unit
is installed underneath the cross
arm, and it communicates with the
controlling system via a twisted pair
RS-485 cable.
e WAC155 consists of a PC board
in a junction box , a cross arm for
mounting the wind sensors and sensor
cables with connector.
Long distance operation
RS-485 communication is half-duplex,
and serial bus termination can be
selected with the on-board jumper
plugs. e transmitter accepts a wide
range of input power and the total
current consumed is typically less
than 10 mA including the sensors. is
allows for remote supply of operating
power. e actual transmitter distance
depends on the selected RS-485
communication speed and is typically
several hundreds of meters.
Normally, only a 4-wire shielded cable
is required for the line between the
WAC155 transmitter and the receiving
end. Two of the four wires provide
the operating power for the system.
e other two are for the RS-485 serial
bus connection from the WAC155
transmitter.
Flexible communications
interface
Wind data is provided in standard
NMEA messages. In addition, a
service connection is available for
conguration and status information.
In the same RS-485 bus, there may be
either single or multiple transmitters.
In the case of a single transmitter,
the transmitter can be congured in
auto-transmit mode, ie. e device
transmits data messages with a
congured interval. If there are several
transmitters in the same bus, autotransmission may not be enabled, but
data can only be polled by query.
Each device in the same bus has a
unique congurable ID, containing 1..5
characters.
Extensive self-diagnostics
When the service connection is open
or the system has been started recently,
the onboard indicator LED ashes red
when any error condition is active.
Also NMEA-messages provided by the
system carry an 'invalid data' status
ag. Input voltage and operating
voltages of the sensors are measured
by an internal A/D-converter. If the
measured value is either below or
above dened limits, an alarm is given.
Wind sensors are cross-checked to
detect whether either one or both
sensors got stuck. If both sensors don’t
move for long time (one day by default),
it is considered as an error situation.
Optional heating power
e WAC155 also provides the sensors
for throughput of optional heating
power. e heating power connection,
if required, calls for an extra pair of
wires. Since the heating elements
typically consume some 500 mA, the
heating power is most conveniently
supplied from a local power source.
Heating control parameters are user
congurable and the default hysteresis
limits are +3˚C ON and +5˚C OFF.
Optional TAMI module
e WAC155 transmitter contains a
TAMI compliant interface and module
slot for various future add-on modules
such as an analog output module to
replace the RS-485 communication
with current loop outputs.
134
Vaisala Instruments Catalog 2009
Ref. B210768EN rev. A
WAC155
Technical Data
WIND
Signal input from sensors
Wind direction 6-bit parallel GRAY code
Wind speed Pulse frequency 0 ... 750 Hz
Output signals
Digital RS-485 serial bus, NMEA compliant data stream
Output accuracy Better than 1% full scale
Output range
For direction 0 ... 360°
For speed 0 ... 76.8 m/s
Signal cable 4 wires minimum (Vin+, Vin–, RS-485 A, RS-485 B)
General
Input operating power 9 ... 15,5 VDC, 9 mA typical incl. sensors
(when power-save mode is enabled)
Heating power 20V/40V AC/DC
Temperature range
operating –55 ... +55 °C (-67 ... +131 °F)
storage –60 ... +70 °C (-76 ... +158 °F)
Humidity 0 ... 100 %RH
Material
Cross arm AI anodized
Junction box AI painted grey
Complies with EMC standard EN 61326-1:1997 + Am1:1998 +
Am2:2001; Generic Environment
Communication Parameters
Baudrate 300, 600, 1200, 2400, 4800, 9600, 19200
Databits 7 or 8
Stopbits 1 or 2
Parity ODD, EVEN, NONE
TxDelay (ms) 0.0 ... 200.0
Default values in Bold.
Dimensions
PC board 114 × 58 mm2
Junction box 125 (w) × 80 (h) × 57 (d) mm
Cross arm length 887 mm
Mounting to a Ø 60 mm pole mast
Weight 1.5 kg
Specications subject to change without prior notice.
©Vaisala Oyj
135
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