All Weather Inc 6030 User manual

All Weather Inc. • 1165 National Drive • Sacramento, CA 95834 • USA • 800.824.5873 • www.allweatherinc.com
User’s
Manual
Rev. E
Model6030
OpticalRainGauge

Copyright ©2011–2016, All Weather, Inc.
All Rights Reserved. The information contained herein is proprietary and is provided solely for the
purpose of allowing customers to operate and/or service All Weather, Inc. manufactured equipment
and is not to be released, reproduced, or used for any other purpose without written permission of
All Weather, Inc.
Throughout this manual, trademarked names might be used. Rather than put a trademark (™)
symbol in every occurrence of a trademarked name, we state herein that we are using the names only
in an editorial fashion and to the benefit of the trademark owner, and with no intention of
infringement. All Weather, Inc. and the All Weather, Inc. logo are trademarks of All Weather, Inc.
Disclaimer
The information and specifications described in this manual are subject to change without notice.
All Weather, Inc.
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Sacramento, CA 95834
Tel.: [phone]
Fax: [phone]
Contact Customer Service
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Model 6030 Optical Rain Gauge User’s Manual
Revision History
Revision
Date
Summary of Changes
B
2011 Oct 31
Removed references to OEM part numbers, replaced installation drawing with
diagrams in the Installation chapter, and better explained options and wiring details
C
2015 July 31
Updated electronics enclosure to use UPCM instead of Serial Sensor Interface and
AC Interface Board
D
2015 Sept 22
Updated Figure 1 and corrected responses to poll commands
E
2016 Nov 28
Added alternative cable wire colors for the sensor head in Figures 8 and 9

Model 6030 Optical Rain Gauge User’s Manual
TABLE OF CONTENTS
1. OVERVIEW.................................................................................................................1
1.1 Accessories.........................................................................................................................1
2. SYSTEM DESCRIPTION............................................................................................2
2.1 Major Components .............................................................................................................2
2.1.1 Sensor Head................................................................................................................2
2.1.2 Electronics Enclosure..................................................................................................3
2.1.3 Universal Power and Communication Module (UPCM)............................................3
3. THEORY OF OPERATION.........................................................................................4
3.1 Sensor Head........................................................................................................................4
4. INSTALLATION...........................................................................................................6
4.1 Siting and Installation Guidelines.......................................................................................6
4.2 Mechanical Installation.......................................................................................................8
4.2.1 Preparation..................................................................................................................8
4.2.2 Mount the Sensor Head...............................................................................................9
4.2.3 Install the Electronics Enclosure...............................................................................12
4.3 Electrical Connections......................................................................................................13
4.3.1 Sensor Connections...................................................................................................17
4.3.2 Connecting the Sensor to the AC Power Line..........................................................17
4.4 UPCM Configuration........................................................................................................18
5. OPERATION WITH AN AWOS DATA COLLECTION PLATFORM ..........................19
5.1 Sensor Interface................................................................................................................19
5.1.1 Physical Level...........................................................................................................19
5.1.2 Link Level.................................................................................................................19
5.1.3 Frame Format............................................................................................................19
5.1.4 Protocol.....................................................................................................................19
5.2 Data Format......................................................................................................................20
5.2.1 Weather Codes..........................................................................................................21
5.2.2 Status Codes..............................................................................................................21
6. MAINTENANCE........................................................................................................22
6.1 Triannual Maintenance.....................................................................................................22
7. SPECIFICATIONS ....................................................................................................24
8. WARRANTY..............................................................................................................26

Model 6030 Optical Rain Gauge User’s Manual
1
1.OVERVIEW
The Model 6030 Optical Rain Gauge optically measures precipitation-induced scintillation and
applies algorithms to determine the precipitation occurrence, type, rate, and water equivalent
accumulation automatically.
The Model 6030 Optical Rain Gauge measures precipitation by detecting the optical
irregularities —known as scintillations —induced by particles falling through a beam of
partially coherent infrared light in the sample volume. The induced scintillations are related to
the characteristics to the precipitation, and the precipitation rate is determined based on the
intensity of these scintillations. In turn, the precipitation rate can be used to determine
precipitation accumulation.
The Model 6030 Optical Rain Gauge is not affected by many of the environmental factors that
cause significant errors with traditional rain gauges. Model 6030 Optical Rain Gauge offers these
features.
Easy Installation
High Sensitivity
Low Maintenance
Minimal Wind Effects
Wide Dynamic Range
Works on Ships and Buoys
No Evaporation or Splash Errors
Not Affected by Insects, Debris, Dust
Applications using traditional tipping bucket rain gauges can all be upgraded easily to use the
Model 6030 Optical Rain Gauge.
The electro-optical design provides for an extremely reliable sensor with a calculated MTBF in
excess of 60,000 hours. Unlike mechanical gauges, which collect the precipitation to measure it,
the Model 6030 Optical Rain Gauge has no collectors or buckets to corrode or clog. The sensors
use automatic gain control circuitry to eliminate the effects of LED output power or dirty optics.
In fact, sensor performance is maintained even when over 75% of the light is blocked!
Diagnostics alert the user if the signal strength is too low for normal operation. Preventative
maintenance, suggested every 6 months, is as simple as cleaning the two optical windows on the
unit.
1.1 ACCESSORIES
The following accessories and replacement parts are available for the Model 6030 Optical Rain Gauge.
Part Number
Description
2715
Universal Power and Communication Module
M442089-00
10 A 250 V, 5x20 mm slow blow fuse
M438130-00
Backup Battery

Model 6030 Optical Rain Gauge User’s Manual
2
2.SYSTEM DESCRIPTION
2.1 MAJOR COMPONENTS
2.1.1 Sensor Head
The sensor head frame is an all-aluminum, welded design. The small box (TX) is the transmitter
unit and contains an infrared LED and lens with a disk heater. The large box (RX) contains a
receiver assembly consisting of a photo diode, a lens with an aperture slit, a disk heater,
electronics, an external thermistor probe, and a connector for the signal/power cable. The wiring
between the two heads is inside the welded head frame.
The transmit and receive lenses are heated by self-regulating positive temperature coefficient
(PTC) thermistor disks to a temperature above the ambient temperature to reduce dew and frost
on the lenses. Depending on the ambient temperature, the current drain for the lens heaters can
change more than 200 mA.
The sensor head is completely sealed from water intrusion at the factory. Exercise care should to
avoid drilling or otherwise puncturing the frame.
A 15 m cable is supplied to connect the sensor head frame to the electronics enclosure.
A mounting plate, an integral part of the sensor head cross arm, is provided to install the head to
a user-supplied mast. Two sets of holes in the mounting plate allow the U-bolts supplied with the
head to clamp the head to either a vertical or horizontal pipe up to 50 mm in diameter.
The 6030 sensor head uses a compact optical system to measure precipitation.
N o t e:
The sensor head frame contains no user serviceable
parts - opening the head will void the warranty!

Model 6030 Optical Rain Gauge User’s Manual
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2.1.2 Electronics Enclosure
The electronics enclosure is a fiberglass NEMA-4X type box with a hinged access door. One
power supply, and AC and RS-485 interface modules with surge protection are mounted to the
base plate of the enclosure. Figure 7 shows the locations of these components inside the
enclosure.
All the units in the enclosure are field-replaceable.
The electronics enclosure is mounted with the supplied fastener hardware using the four (4)
mounting holes on the enclosure.
2.1.3 Universal Power and Communication Module (UPCM)
The Universal Power and Communication Module is built in to the Optical Rain Gauge, and
provides power and a serial interface for the Optical Rain Gauge.
The electronics enclosure contains the processing electronics, power supplies, and
surge protection circuits.
N o t e:
Exercise care to avoid drilling or otherwise puncturing the
electronics enclosure.

Model 6030 Optical Rain Gauge User’s Manual
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3.THEORY OF OPERATION
3.1 SENSOR HEAD
The sensor measures precipitation by detecting the optical irregularities induced by particles falling
through a beam of partially coherent infrared light (in the sample volume). These irregularities
are known as scintillation. The twinkling of stars is a familiar example of scintillation. By
detecting the intensity of the scintillations which are characteristic of precipitation, the precipita-
tion rate is determined. Precipitation is measured using the sensor head “in-beam” optics.
Figure 1. Optical Rain Gauge Theory of Operation
The Model 6030 Optical Rain Gauge consists of these components.
A transmit modulator and infrared LED (TX)
A transmitter optical lens assembly
A receiver optical lens assembly
A photo detector and preamplifier (RX)
The sensor head is a self-contained unit consisting of electro-optical components,
heaters, a microprocessor, and integral cabling to connect with the electronics
enclosure.

Model 6030 Optical Rain Gauge User’s Manual
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An Automatic Gain Controlled (AGC) normalizer
A signal processor
A temperature probe
A microprocessor and communications subsystem
The transmitter portion of the sensor head uses an infrared LED as a light source that is modu-
lated to eliminate interference in the system caused by background light. The LED has a very
long life time, has a relatively low power draw, is invisible to the eye, and presents no radiation
hazard to the user.
The LED is housed in the smaller of the sensor head boxes. A lens is used to collimate the LED’s
carrier-wave modulated light into a slightly diverged beam. The transmit and receive lenses are
both heated by self-regulating positive temperature coefficient (PTC) thermistor disks to a tem-
perature just above the ambient temperature to reduce dew and frost on the lenses.
The larger sensor head rectangular box houses receive optics, DC regulator, the AGC, signal
processing electronics, temperature probe, and microprocessor. The receive lens focuses the
transmitted light onto a photo diode. The scintillations in light intensity are thus detected and
amplified. A wide dynamic range Automatic Gain Control (AGC) circuit normalizes the pre-
cipitation-induced scintillation signal to the carrier-wave modulated light. Thus errors from var-
iations in the source intensity caused by LED aging or dirt on the lenses are eliminated. The
demodulated scintillation signal is then further filtered, processed, and averaged. The statistical
average of the measured scintillation signals gives an accurate measurement of instantaneous
precipitation rates.
The microprocessor uses an adaptive baseline technique to optimize the sensitivity of the Optical
Rain Gauge continuously. This technique ensures that the sensitivity is not affected by normal
atmospheric turbulence, and it minimizes the chance of false alarms (such as reporting precipita-
tion when none occurs). The processor uses the scintillation signal and temperature probe data to
determine the precipitation type and calculates the total water equivalent with the following
formula.
󰇛󰇜   󰇛󰇜󰇛󰇜
RR is the precipitation intensity, and kis a constant that depends on the ambient temperature, T,
as follows.
T> 3°C
k= 1
T< =4°C
k= 0.607
-40°C < T < 30°C
   
 
The microprocessor also provides diagnostic data about the condition of the sensor. The output is
an RS-232 data string that is converted to RS-485 by the Serial Sensor Processor in the electron-
ics enclosure.

Model 6030 Optical Rain Gauge User’s Manual
6
4.INSTALLATION
4.1 SITING AND INSTALLATION GUIDELINES
In general, the sensor should be located on level or slightly sloping ground where the sensor site
will be exposed to the same environment as the area around it. Ideally, the area around the site
should be free of buildings, trees, and other obstructions.
All Weather, Inc. recommends that the siting and installation follow the general guidelines
established by the Office of the Federal Coordinator for Meteorology (OFCM). The Federal
Standard for Siting Meteorological Sensors at Airports, OFCM document # FSM-S4-1987,
makes the following recommendations.
1. Distance from Obstructions —The distance between the sensor and obstructions such as
trees or buildings should be at least 2 times the height of the obstruction on all sides. For
example, if a tree20 m high is located alongside the sensor, the sensor should be at least
40 m away from the tree. This restriction reduces the effects of wind turbulence created
by the nearby obstruction and makes the precipitation measurement more representative.
Do not locate the sensor where tree branches or wires will hang over the sensor!
2. Separation from Turbulence and Contamination Sources —Do not mount the sensor near
building exhaust vents, strobe lights, or sources of smoke or steam. Where possible,
locate the unit as far away from runways and roads as possible to reduce optics fouling
from wind-blown road dirt. An ideal minimum distance is at least 30 m.
3. Sensor Height, Rigidity, Verticality, and Orientation —The OFCM recommends that the
Optical Rain Gauge be mounted at a height of 10 ft (3 m). This height is not always
possible because of constraints imposed by the site. Mounting the sensor head lower than
2 m or higher than 5 m is not generally recommended.
4. For AWOS installations, All Weather, Inc. recommends that the sensor head should be
mounted on a mast with a diameter of 50 mm (2") that is set in a concrete foundation is
recommended. The electronics enclosure should be nearby, keeping in mind that the
cable extending from the sensor head is 15 m long.
The installation must be rigid so that wind-induced vibration does not cause false alarms.
This can be accomplished by mounting the sensor to a thick wall pipe such as “Schedule
40” type or to a rigid boom arm 1 m in length or shorter. The Optical Rain Gauge may be
mounted on the top of a building if it located near the center of the building away from
the wind turbulence that may occur near the edges.
The sensor head must be mounted vertical within ±2 degrees so that the line aperture on
the in-beam lens is horizontal.
The Model 6030 Optical Rain Gauge may be installed almost anywhere outdoors. An
area free and clear of obstructions and contamination sources will help insure good
sensor performance.