Xylem SDI-12 User Manual
USER MANUAL
V2.0
(FOR FIRMWARE V2.0)
SDI-12 RADAR
WATER LEVEL SENSOR
D36 0514
CONTENTS & WARRANTY
Warranty.................................................................................1
Chapter 1: Introduction.......................................................2
Features................................................................................
Built-in LCD Display............................................................
Communications.................................................................
Fast Mode Data Logging....................................................
“NOAA” Mode measurement............................................
Fast Measure Mode............................................................
FCC Approval......................................................................
Chapter 2: Installation & Maintenance............................6
Installation Techniques.......................................................
General Installation Recommendations...........................
Mounting the Radar Unit - Vertical Alignment................
Making Connections..........................................................
Grounding Your Radar.......................................................
Over Cable.....................................................................
Wireless Radio..............................................................
Connecting Your Data Logger.........................................
Programming Your SDI-12 Data Recorder.....................
Programming the SDI-12 Interface.................................
Setup and Test Procedure...............................................
Programming the Radar Sensor......................................
Built-in LCD Display..........................................................
Chapter 3: SDI-12 Command & Response Protocol...17
Command Summary.........................................................
Measure Command..........................................................
“aM1” (NOAA) Measure Command...............................
“aM2” 1 Minute Average Measure Command..............
“aM3” 15 Second Average Measure Command...........
Concurrent Measurement Command............................
Concurrent “aC1!” Command.........................................
Concurrent “aC2!” Command.........................................
Send Data Command......................................................
Measurements with CRC.................................................
Continuous Measurements.............................................
Send Acknowledge Command......................................
Initiate Verify Command..................................................
Send Identification Command........................................
Change Sensor Address Command..............................
Extended Set_Current_Stage Command......................
Extended Read/Write Stage_Offset and Stage_Slope.
Extended Read Number_of_Measurements.................
Extended Write Number_of_Measurements................
Extended “XTEST”.............................................................
Chapter 4: Appendix.........................................................35
Appendix A: Specifications.............................................
Appendix B: FCC Equipment Authorization.................
3
4
4
4
4
5
5
7
8
8
9
9
9
11
12
13
13
13
14
15
19
19
21
23
24
25
26
26
27
28
28
28
28
29
30
31
31
33
33
34
36
37
Contents & Warranty
“WATERLOG™ PRODUCTS MANUFACTURED BY YELLOW SPRINGS INSTRUMENTS CO., INC.
are warranted by Yellow Springs Instruments Co., Inc. (“YSI”) to be free from defects in materials
and workmanship under normal use and service for twelve (12) months from date of shipment
unlessotherwise specified in the corresponding YSI pricelist or product manual.
WaterLOG™ products not manufactured, but that are re-sold by YSI, are warranted only to the
limits extended by the original manufacturer. Batteries, desiccant, and other consumables have
no warranty. YSI’s obligation under this warranty is limited to repairing or replacing (YSI’s option)
defective products,which shall be the sole and exclusive remedy under this warranty.
The customer shall assume all costs of removing, reinstalling, and shipping defective products to YSI.
YSI will return such products by surface carrier prepaid within the continental United States of America.
To all other locations, YSI will return such products best way CIP (Port of Entry) INCOTERM® 2010,
prepaid. This warranty shall not apply to any products which have been subjected to modification,
misuse, neglect, improper service, accidents of nature, or shipping damage. This warranty is in lieu
of all other warranties, expressed or implied. The warranty for installation services performed by YSI
such as programming to customer specifications, electrical connections to products manufactured by
YSI, and product specific training, is part of YSI’s product warranty. YSI EXPRESSLY DISCLAIMS AND
EXCLUDES ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR
PURPOSE. YSI is not liable for any special, indirect, incidental, and/or consequential damages.”
A complete TERMS AND CONDITIONS OF SALE can be viewed at:
http://www.ysi.com/terms-and-conditions.php
This user manual is a guide for the H-3611/12/13 Radar Level Series
. For more information, updated
manuals, brochures, technical notes, and supporting software on the H-3611/12/13 Radar
refer to waterlog.com/radar or contact your sales representative.
For additional assistance, please contact us at +1.435.753.2212 or sales@waterlog.com
, please
1
01 /
INTRODUCTION
2
Introduction
The WaterLOG® Radar Series consist of
the H-3611, H-3612 and H-3613 products.
Typical applications include non-contact
measurement of river, lake and reservoir
water level. The sensor makes multiple
distance measurements, averages the
results and converts the measurement
data into Stage in units of Feet, Meters or
other engineering units.
The Radar Series is easy to use and works
with any data recorder/logger with a SDI12 interface. They are powered from the
+12V wire of the 3-wire SDI-12 bus. The
Serial-Digital Interface (SDI-12) is ideal
for data logging applications with the
following requirements:
Battery powered operation with minimal current drain
•
• Measurement data is transmitted digitally over long cable lengths without error
• Multiple sensors on a simple three-wire cable
• Up to 250 feet of cable between a sensor and the data recorder (Use of an H-423, SDI-12 to RS485 or an
H-4500 fiberoptic media converter extends the range to 1000’s of feet)
Features
Below is a quick overview of the common features of all Radar series products.
•
Simple to install, use, and maintain
• Non-contact level measurement eliminates the need for stilling wells and other infrastructure.
• Undamaged by ice, logs or debris
• ±3.0mm accuracy with standard model
• -40 ° C to +80 ° C operation
• NEMA 4x enclosure is suitable for outdoor installations
• Stainless steel horn (H-3611/ H-3612)
• Frequency range - approx 26 Ghz
• Built-in LCD screen for monitor and setup
• Low current operation (8.0 mA typical standby)
• Continuous operation, no warmup or “lock on” needed
• Extended SDI-12 commands for setting the Stage to the current water elevation.
• Built in 3 or 6 minute “NOAA” mode measurements.
• Optional fast mode sends the service request within 55mS for sustained 1-second data logging.
Description
The Radar Level gauge consists of an integrated microwave transmitter and sensor together with a
horn antenna. The horn antenna serves to focus the transmitted signal as well as to receive the
reflected echo. A built-in SDI-12 interface provides low power operation, data processing and
SDI-12 communications with the data logger.
3
INTRODUCTION
Built-in LCD Display
The Radar sensor has a built-in LCD
display which normally shows Distance
(distance from the radar unit to the
water). The display has three buttons and
can be used to monitor or edit the radar
unit configuration. The LCD display has
a short cord and can be detached from
the radar housing for convenience.
Communications
The Radar sensor is a stand-alone
instrument that provides an SDI-12
output for communications with a
datalogger. The sensor is supplied with
a liquid-tight fitting and two 6- foot cables. One cable is convenient for making connections to
your data logger, the second cable used to connect to a laptop computer when using the TofTool
configuration and diagnostic program.
Fast Mode Data Logging
The Radar response to an “aM!” command is “0044” (4-seconds, 4-parameters). The actual
measurement completes very quickly and the service request is sent within 530ms. The reported
4-second value allows time for retries when troubleshooting the internal connection between the
SDI-12 interface and the radar unit. Unfortunately most data loggers cannot sustain a 1-second
logging interval even if the sensor responds within 500mS. For making measurements at a
sustained 1-second measurement interval two options are available as explained below.
“NOAA” Mode Measurement
The Radar supports the “aM1” measurement. The H-3611 internally performs the following
measurement sequence.
1. Makes 181 measurements at a precise 1 second interval.
2. Computes the standard deviation for the data set.
3. Multiplies the standard deviation by 3 to obtain a High and Low outlier threshold.
4. Sifts through the data set and discards data points above and below the outlier thresholds.
5. Computes the standard deviation again for the data set with the outliers removed.
The standard deviation is computed as follows:
1. Compute the mean for the data set
2. Compute the deviation by subtracting the mean from each value
3. Square each individual deviation
4
Introduction
4. Divide by one less than the sample size
5. Take the square root
The “aM1” command response is “01844” (184 seconds, 4- parameters). The sensor buffer will
contain 4 parameters; mean, standard deviation, number of outliers and battery voltage.
If the built in “NOAA” mode is not workable, the H-3611 supports an alternate “fast measure”
mode.
Fast Measure Mode
Normally, the Radar transmits the service request within 530mS of receipt of the command. As
with many data loggers, this leaves insufficient time to sustain continuous measurements once
per second. The Power_Mode is an internal setting which places the H-3611 in a fast measure
mode. In this mode, the Radar is always awake and automatically collecting data from the
radar unit at a 1-second interval and stores the previous six minutes of data in the stack. In this
mode the sensor uses additional power. When an “aM!” measurement is received, the sensor
response is “0014” (1-seconds, 4-parameters). The service request is sent within 55mS of receipt
of the command (170mS of receipt of the break). This leaves plenty of time for a data logger to
collect the data while sustaining a 1-second logging interval. The data placed in the sensor buffer
is the results of the previous internal measurement (1-second old). The data logger must
implement its own internal NOAA or other filtering and averaging computations.
When in fast measure mode the radar makes continuous measurements which allows a different
type of NOAA mode measurement to take place. When in fast measure mode the “aM1!”
command is replaced with a command that takes the data from the previous six minutes and
performs the same procedure as the NOAA mode measurements, namely:
1. Collect a set of 1-Hz samples centered in the previous six minute time block, the
length of which is selected by the user (ranging from 1-360)
2. Computes the standard deviation for the data set.
3. Multiplies the standard deviation by 3 to obtain a High and Low outlier threshold.
4. Sifts through the data set and discards data points above and below the outlier thresholds.
5. Computes the mean and standard deviation again for the data set with the outliers removed.
In addition to the “aM1!” command, the “aM2!” and “aM3!” commands have been added which
take the simple average and standard deviation of the previous 1 minute and 15 second data sets
respectively. All of these commands have concurrent counterparts as well.
FCC Approval
This device complies with part 15 of the FCC Rules. Operation is subject to the following two
conditions: (1) This device may not cause harmful interference, and (2) this device must accept
any interference received, including interference that may cause undesired operation.
5
INSTALLATION
02 /
& MAINTENANCE
6
Installation & Maintenance
The Radar is a time-of-flight microwave radar level sensor. It excels in applications where ice, logs,
floating debris and boat traffic can damage stilling wells and other infrastructure. When installed
on a bridge over shallow streams having sandy bottoms the radar can be moved from location to
location as the river shifts channel position after storm events.
Installation Techniques
For installations where vandalism is of concern or additional protection is needed, many users
prefer to install the radar unit in a protective housing. The housing provides a convenient location
for installing other gauge station equipment such as a battery or data logger. Several housings
are available from WaterLOG, please contact the factory for further information. WaterLOG also
offers optional installation packages that have a solar panel, battery and short range
telemetry radio for communicating with a nearby gauge station.
Several typical installations are shown below.
7
INSTALLATION & MAINTENANCE
General Installation Recommendations
Before proceeding with the installation, please consider several site preparation and maintenance
issues. The Radar Series has been designed to operate safely in accordance with current technical,
safety and EU standards. Personnel must be authorised and suitably qualified. The manual must
have been read and understood, and the instructions followed.
Warning: Working over water or on tall structures can be dangerous. Use a safety harness,
fall arrest device, life saver and/or other safety equipment when conditions warrant.
Follow these guidelines when selecting a location for the radar gauge:
• The radar unit is a precision instrument and should not be jarred or dropped.
• The sensor must be mounted rigidly to prevent movement from wind and vibration.
• The antenna horn must be aligned within 1 ° of vertical to prevent trigonometric measurement errors.
• Make certain the sensor is mounted high enough to avoid being submerged during high water or ood
conditions.
• The sensor is rated NEMA 4x and can be mounted outdoors in unprotected locations.
• The operating temperature range for the sensor is –40 ° C to 80 ° C.
• The sensor should be mounted above the smoothest portion of the water surface. Generally between piers
of a bridge structure. However on bridges with long spans between the piers there will be more vibration
on the bridge. To moderate the vibration in these situations mount the radar 1/4 to 1/3 the span distance
from the pier.
• There should be a clear path between the sensor and the water to avoid false reections. Try to locate the
sensor to keep the beam path (8 ° for 4-inch horn, 10 ° for 3-inch horn) clear of excessive turbulence,
splashing, waves, pipes, wires and other obstructions.
• Avoid submerged obstructions such as rocks or bridge piers that disturb or distort the water level.
• The mounting location should also avoid horizontal structural surfaces such as beams, brackets, and side
wall joints because these surfaces tend to reflect a strong false signal. If these cannot be avoided the display
can be used to map the radar beam profile and optimize the profile by means of electronic suppression of
interference echoes.
• Be aware that bridges and other large structures expand and contract with temperature. The bridge height
can change a few inches with diurnal temperature changes. Trucks and other traffic loads can cause transient
changes to the bridge height.
Mounting the Radar Unit - Vertical Alignment
Make certain the horn antenna is aligned within 1 ° of vertical. If the antenna is not vertical a
trigonometric measurement error with respect to the water will occur and the maximum range will
be reduced due to the off-axis return signal.
8
Installation & Maintenance
Making Connections
Since the Radar can be exposed to the
sun and weather, a cable rated for water
immersion (rain) and sunlight resistance
is required. A polyurethane or similar
sunlight and waterproof rated cable is
recommended. Do not use utility PVC
or other wiring materials which can
become brittle or crack when exposed to
ultraviolet radiation from the sun.
If conduit is used to connect to the Radar,
remove and discard the liquid-tight cord
retainer. If metal conduit is used, the
conduit must be grounded. When using
conduit the entry must be sealed with
silicone or other sealant to prevent moisture from entering the Radar enclosure via the conduit piping.
The thermal mass of the casting will cause water vapor to internally condense and accumulate with
changes in the weather.
Caution: Remove all power from the unit before making any connections.
Liquid Tight Fitting
SDI-12 Connections
Warning: All wiring must be done by qualified individuals in accordance with applicable
codes such as the ANSI/NFPA 70 specifications or the
Canadian Electrical Code Part 1.
Grounding Your Radar
The following graphic illustrations are the recommended methods for grounding the Radar. These
grounding methods will work if the guidelines are strictly followed. It should be mentioned that not
much can protect your site if it suffers a direct lightning strike. However, these general grounding
techniques can certainly help protect the equipment from normal occurrences. It is hoped that this
information will serve as a reference guide to grounding your Radar.
Grounding Your Radar Over Cable
Grounding the Radar is a simple yet subtle thing to do. Figures on page 10 show the preferred
methods for grounding a radar gauge over a cable. A metal conduit is to be used. If junction
boxes or pull boxes are used, they are to be metal as well. The metal conduit will provide a
conducting path to ground for the radar enclosure and also act as a shield that will conduct away
electrical noise. If a flex conduit is used at the radar enclosure or at the gauge house, this
conduit must be a conducting type of conduit. Note: you must also use a conducting
connector for conducting flex conduit. The electrical cable is to have a shield and at least 3
conductors. The wire conductor gauge of 20awg is recommended for most applications, but
you may certainly use 18 or 16 gauge conductors as well.
9
INSTALLATION & MAINTENANCE
Layout of Hard Wire Radar Installation
10
Layout of Hard Wire Radar Installation with Insulator
Loading...