CS SR50A User manual

INSTRUCTION MANUAL
SR50A, SR50A-316SS,
and SR50AH
Sonic Ranging Sensors
Revision: 10/16
Copyright © 2007-2016
Campbell Scientific, Inc.

Limited Warranty
“Products manufactured by CSI are warranted by CSI to be free from defects in
materials and workmanship under normal use and service for twelve months
from the date of shipment unless otherwise specified in the corresponding
product manual. (Product manuals are available for review online at
www.campbellsci.com.) Products not manufactured by CSI, but that are resold
by CSI, are warranted only to the limits extended by the original manufacturer.
Batteries, fine-wire thermocouples, desiccant, and other consumables have no
warranty. CSI’s obligation under this warranty is limited to repairing or
replacing (at CSI’s option) defective Products, which shall be the sole and
exclusive remedy under this warranty. The Customer assumes all costs of
removing, reinstalling, and shipping defective Products to CSI. CSI will return
such Products by surface carrier prepaid within the continental United States of
America. To all other locations, CSI will return such Products best way CIP
(port of entry) per Incoterms ® 2010. 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 CSI such as programming to customer specifications, electrical
connections to Products manufactured by CSI, and Product specific training, is
part of CSI's product warranty. CSI EXPRESSLY DISCLAIMS AND
EXCLUDES ANY IMPLIED WARRANTIES OF MERCHANTABILITY
OR FITNESS FOR A PARTICULAR PURPOSE. CSI hereby disclaims,
to the fullest extent allowed by applicable law, any and all warranties and
conditions with respect to the Products, whether express, implied or
statutory, other than those expressly provided herein.”

Assistance
Products may not be returned without prior authorization. The following
contact information is for US and international customers residing in countries
served by Campbell Scientific, Inc. directly. Affiliate companies handle repairs
for customers within their territories. Please visit www.campbellsci.com to
determine which Campbell Scientific company serves your country.
To obtain a Returned Materials Authorization (RMA), contact CAMPBELL
SCIENTIFIC, INC., phone [phone]. Please write the issued RMA
number clearly on the outside of the shipping container. Campbell Scientific’s
shipping address is:
CAMPBELL SCIENTIFIC, INC.
RMA#_____
815 West 1800 North
Logan, Utah 84321-1784
For all returns, the customer must fill out a “Statement of Product Cleanliness
and Decontamination” form and comply with the requirements specified in it.
The form is available from our website at www.campbellsci.com/repair. A
completed form must be either emailed to [e-mail] or faxed to
[phone]. Campbell Scientific is unable to process any returns until we
receive this form. If the form is not received within three days of product
receipt or is incomplete, the product will be returned to the customer at the
customer’s expense. Campbell Scientific reserves the right to refuse service on
products that were exposed to contaminants that may cause health or safety
concerns for our employees.

Safety
DANGER — MANY HAZARDS ARE ASSOCIATED WITH INSTALLING, USING, MAINTAINING, AND WORKING ON OR AROUND
TRIPODS, TOWERS, AND ANY ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS, ENCLOSURES,
ANTENNAS, ETC. FAILURE TO PROPERLY AND COMPLETELY ASSEMBLE, INSTALL, OPERATE, USE, AND MAINTAIN TRIPODS,
TOWERS, AND ATTACHMENTS, AND FAILURE TO HEED WARNINGS, INCREASES THE RISK OF DEATH, ACCIDENT, SERIOUS
INJURY, PROPERTY DAMAGE, AND PRODUCT FAILURE. TAKE ALL REASONABLE PRECAUTIONS TO AVOID THESE HAZARDS.
CHECK WITH YOUR ORGANIZATION'S SAFETY COORDINATOR (OR POLICY) FOR PROCEDURES AND REQUIRED PROTECTIVE
EQUIPMENT PRIOR TO PERFORMING ANY WORK.
Use tripods, towers, and attachments to tripods and towers only for purposes for which they are designed. Do not exceed design limits.
Be familiar and comply with all instructions provided in product manuals. Manuals are available at www.campbellsci.com or by
telephoning [phone] (USA). You are responsible for conformance with governing codes and regulations, including safety
regulations, and the integrity and location of structures or land to which towers, tripods, and any attachments are attached. Installation
sites should be evaluated and approved by a qualified engineer. If questions or concerns arise regarding installation, use, or
maintenance of tripods, towers, attachments, or electrical connections, consult with a licensed and qualified engineer or electrician.
General
•Prior to performing site or installation work, obtain required approvals and permits. Comply
with all governing structure-height regulations, such as those of the FAA in the USA.
•Use only qualified personnel for installation, use, and maintenance of tripods and towers, and
any attachments to tripods and towers. The use of licensed and qualified contractors is highly
recommended.
•Read all applicable instructions carefully and understand procedures thoroughly before
beginning work.
•Wear a hardhat and eye protection, and take other appropriate safety precautions while
working on or around tripods and towers.
•Do not climb tripods or towers at any time, and prohibit climbing by other persons. Take
reasonable precautions to secure tripod and tower sites from trespassers.
•Use only manufacturer recommended parts, materials, and tools.
Utility and Electrical
•You can be killed or sustain serious bodily injury if the tripod, tower, or attachments you are
installing, constructing, using, or maintaining, or a tool, stake, or anchor, come in contact with
overhead or underground utility lines.
•Maintain a distance of at least one-and-one-half times structure height, 20 feet, or the distance
required by applicable law, whichever is greater, between overhead utility lines and the
structure (tripod, tower, attachments, or tools).
•Prior to performing site or installation work, inform all utility companies and have all
underground utilities marked.
•Comply with all electrical codes. Electrical equipment and related grounding devices should be
installed by a licensed and qualified electrician.
Elevated Work and Weather
•Exercise extreme caution when performing elevated work.
•Use appropriate equipment and safety practices.
•During installation and maintenance, keep tower and tripod sites clear of un-trained or non-
essential personnel. Take precautions to prevent elevated tools and objects from dropping.
•Do not perform any work in inclement weather, including wind, rain, snow, lightning, etc.
Maintenance
•Periodically (at least yearly) check for wear and damage, including corrosion, stress cracks,
frayed cables, loose cable clamps, cable tightness, etc. and take necessary corrective actions.
•Periodically (at least yearly) check electrical ground connections.
WHILE EVERY ATTEMPT IS MADE TO EMBODY THE HIGHEST DEGREE OF SAFETY IN ALL CAMPBELL SCIENTIFIC PRODUCTS,
THE CUSTOMER ASSUMES ALL RISK FROM ANY INJURY RESULTING FROM IMPROPER INSTALLATION, USE, OR
MAINTENANCE OF TRIPODS, TOWERS, OR ATTACHMENTS TO TRIPODS AND TOWERS SUCH AS SENSORS, CROSSARMS,
ENCLOSURES, ANTENNAS, ETC.

i
Table of Contents
PDF viewers: These page numbers refer to the printed version of this document. Use the
PDF reader bookmarks tab for links to specific sections.
1. Introduction ................................................................1
2. Precautions ................................................................1
3. Initial Inspection.........................................................1
4. QuickStart...................................................................2
5. Overview .....................................................................4
6. Specifications.............................................................5
7. Installation ..................................................................7
7.1 Sensor Mounting ..................................................................................7
7.1.1 Beam Angle ..................................................................................7
7.1.2 Mounting Height...........................................................................7
7.1.2.1 Reference Point ..................................................................8
7.1.3 Mounting Options .........................................................................8
7.2 SDI-12 Wiring ...................................................................................10
7.3 SDI-12 Programming.........................................................................10
7.3.1 SDI12Recorder() Instruction.......................................................11
8. Operation..................................................................11
8.1 Quality Numbers ................................................................................12
8.2 Temperature Compensation ...............................................................12
8.3 SDI-12 Measurements........................................................................13
8.3.1SDI-12 Addresses .......................................................................13
8.3.2 SDI-12 Commands .....................................................................13
9. Maintenance and Troubleshooting .........................15
9.1 Disassembly/Assembly Procedures ...................................................15
9.2 Data Interpretation and Filtering ........................................................18
9.2.1 Data Interpretation ......................................................................18
9.2.2 Data Filtering ..............................................................................18
Appendices
A. Importing Short Cut Code Into CRBasic Editor ... A-1
B. Example Programs................................................. B-1
B.1 SDI-12 Example Programs ..............................................................B-1
B.1.1 CR1000 SDI-12 Program..........................................................B-1

Table of Contents
ii
B.1.2 CR6 SDI-12 Program............................................................... B-3
B.2 RS-232 Example Programs ............................................................. B-6
B.2.1 CR1000 RS-232 Program......................................................... B-6
B.3 RS-485 Example Programs ............................................................. B-9
B.3.1 CR1000 Programming Example Using an MD485 and
SC110 9-pin Male Connector ............................................... B-9
B.3.2 CR6 RS-485 Programming Example ..................................... B-13
B.4 Heater Program Examples............................................................. B-16
C. Jumper Settings ..................................................... C-1
D. RS-232 and RS-485 Operation...............................D-1
D.1 RS-232 Operation............................................................................ D-1
D.1.1 RS-232 Wiring ......................................................................... D-1
D.2 RS-485 Operation............................................................................ D-2
D.2.1 RS-485 Wiring Using a MD485............................................... D-3
D.3 RS-485 Wiring to a CR6 Datalogger............................................... D-4
D.4 RS-232 and RS-485 Settings........................................................... D-4
D.4.1 Baud Rate Setting..................................................................... D-6
D.4.2Address..................................................................................... D-7
D.4.3 Operational Mode Setting ........................................................ D-7
D.3.3.1 Measure in Poll Mode.................................................... D-7
D.3.3.2 Auto Measure Auto Output Mode ................................. D-7
D.3.3.3 Auto Measure Polled Output Mode ............................... D-7
D.4.4 Distance to Target or Depth ..................................................... D-8
D.4.5 Distance to Ground .................................................................. D-8
D.4.6 Measurement Interval Units ..................................................... D-8
D.4.7 Measurement Interval Value .................................................... D-8
D.4.8 Output Unit .............................................................................. D-9
D.4.9 Quality Output.......................................................................... D-9
D.4.10 Diagnostics Output................................................................... D-9
D.5 Serial Commands ............................................................................ D-9
D.5.1 Setup Command ....................................................................... D-9
D.5.2 Poll Command.......................................................................... D-9
D.5.3 Information Command ............................................................. D-9
D.5.4 Temperature Input Command ................................................ D-10
D.6 RS-232/RS-485 Data Output Format ............................................ D-10
D.6.1 Measurement Output.............................................................. D-10
D.6.2 Information Message Output.................................................. D-12
E. Tera Term QuickStart............................................. E-1
E.1 Configure Tera Term for Serial 9600 BPS Communication ............E-1
E.2 Firmware Update..............................................................................E-5
E.2.1 Configure Tera Term to Send SR50A/T Firmware Update ......E-5
E.2.2 Sending New Firmware to a SR50A/T Sensor..........................E-6
F. SR50AH Heater Operation ..................................... F-1
F.1 Heater Specifications........................................................................F-1
F.1.2 Heating Cable Requirements.....................................................F-1
F.2 Heater Maintenance..........................................................................F-2

Table of Contents
iii
Figures
7-1. Beam Angle Clearance.........................................................................7
7-2. Distance from Edge of Transducer Housing to Grill ...........................8
7-3. SR50A Mounted to a Crossarm via the 19517 Mounting Kit ..............9
7-4. Another Angle of the 19517 Mounting Kit..........................................9
7-5. SR50A Mounted to a 19484 Mounting Stem.......................................9
7-6. SR50A-316SS Mounted to a Crossarm with the 19484 and Nu-Rail
Fitting .............................................................................................10
9-1. Disconnect Cable from Sensor...........................................................15
9-2. Remove Six Screws from the Transducer Housing............................16
9-3. Remove Transducer Housing and Disconnect Wires.........................16
9-4. Location of Desiccant in Transducer Housing Assembly ..................17
9-5. Remove and Replace Desiccant .........................................................17
9-6. Remove the Two Flat Phillips Screws to Expose the PCB ................18
C-1. Jumper Settings................................................................................C-1
D-1. RS-232 DB9 Connector Description............................................... D-1
D-2. SR50A to MD485 Wiring ............................................................... D-3
D-3. Initial Terminal Window in Device Configuration Utility .............. D-5
D-4. SR50A Setup Menu ........................................................................ D-5
E-1. Tera Term New Connection............................................................. E-1
E-2. Setup Selections ...............................................................................E-2
E-3. Terminal Configuration.................................................................... E-2
E-4. Windows Setup Changes ................................................................. E-3
E-5. Setting the Font Size ........................................................................ E-3
E-6. Configuring the Serial Port .............................................................. E-4
E-7. Testing the Configuration ................................................................ E-4
E-8. Configuring the Com Port to Send an Operating System................. E-6
E-9. Jumper Settings................................................................................ E-6
F-1. SR50AH Heater Option ................................................................... F-2
F-2. Complete Transducer Assembly with Power Connection................ F-4
Tables
7-1. Wire Color, Function, and Datalogger Connection............................10
8-1. Quality Number Description ..............................................................12
8-2. SDI-12 Commands.............................................................................13
B-1. Wiring for CR1000 and CR6 SDI-12 Example Programs ...............B-1
B-2. Wiring for CR1000 and CR6 RS-232 Example Programs...............B-6
B-3. 14291 Field Power Cable Connections ............................................B-9
B-4. 107 and SC110 Wiring for CR1000 RS-232 Example Program ......B-9
B-5. SR50A (Configured for MD485) Wiring to MD485 (9-pin
connector plugged into MD485 RS-232 port) ............................B-10
B-6. Wiring for CR6 RS-485 Program ..................................................B-13
B-7. Wiring for CR1000 and CR6 Heater Example Programs ..............B-16
D-1. SR50A RS-232 Interface Wiring .................................................... D-2
D-2. SR50A Datalogger COM Port Wiring ............................................ D-2
D-3. Connections for RS-485 Mode........................................................ D-3
D-4. Connections for CR6 RS-485 Mode ............................................... D-4
D-5. RS-232 and RS-485 Settings........................................................... D-6
CRBasic Examples
B-1. CR1000 SDI-12 Program.................................................................B-1
B-2. CR6 SDI-12 Program.......................................................................B-3
B-3. CR1000 RS-232 Program ................................................................B-6

Table of Contents
iv
B-4. CR1000 Programming Example Using an MD485 and SC110
9-pin Male Connector ................................................................ B-10
B-5. CR6 RS-485 Programming Example ............................................ B-13
B-6. CR1000 Heater Program Example ................................................ B-16
B-7. CR6 Heater Program Example ...................................................... B-19

1
SR50A-Series Sonic Ranging Sensor
1. Introduction
The SR50A, SR50A-316SS, and SR50AH are sonic ranging sensors that
provide a non-contact method for determining snow or water depth. They
determine depth by emitting an ultrasonic pulse and then measuring the elapsed
time between the emission and return of the pulse. An air temperature
measurement is required to correct for variations of the speed of sound in air.
Differences between the SR50A, SR50A-316SS, and SR50AH:
•SR50A: standard anodized aluminum body
•SR50A-316SS: marine grade 316L stainless steel body with a
parylene-coated transducer head
•SR50AH: standard anodized aluminum body with a heated transducer
head to prevent riming
This manual provides information only for CRBasic dataloggers.
It is also compatible with our retired Edlog dataloggers. For Edlog
datalogger support, see an older manual at
www.campbellsci.com/old-manuals.
2. Precautions
•READ AND UNDERSTAND the Safety section at the front of this
manual.
•Never open the sensor while it is connected to power or any other device.
•Always disconnect the sensor using the connector or disconnect the cable
wires from their termination points.
•Never operate the sensor with the shield wire disconnected. The shield
wire plays an important role in noise emissions and susceptibility as well
as transient protection.
•Follow local regulations (see Compliance in Section 6, Specifications (p. 5)).
3. Initial Inspection
•Upon receipt of the sensor, inspect the packaging for any signs of shipping
damage and, if found, report the damage to the carrier in accordance with
policy. The contents of the package should also be inspected and a claim
filed if any shipping related damage is discovered.
NOTE

SR50A-Series Sonic Ranging Sensors
2
4. QuickStart
Short Cut is an easy way to program your datalogger to measure the SR50A
and assign datalogger wiring terminals. Short Cut is available as a download on
www.campbellsci.com and the ResourceDVD. It is included in installations of
LoggerNet, PC200W, PC400, or RTDAQ.
Use the following procedure to get started.
A temperature measurement is required. For this tutorial, the 107-
L thermistor is used.
1. Open Short Cut. Click New Program.
2. Select Datalogger Model and Scan Interval (60 second or higher scan
interval is recommended). Click Next.
NOTES

SR50A-Series Sonic Ranging Sensors
3
3. Under the Available Sensors and Devices list, select the Sensors |
Temperature folder. Select 107 Temperature Probe. Click to move
the selection to the Selected device window. Use the data default of degree
Celsius.
4. Under the Available Sensors and Devices list, select the Sensors |
Miscellaneous Sensors folder. Select SR50A Sonic Ranging Sensor
(SDI-12 Output). Click to move the selection to the Selected device
window. Data defaults to meters, which can be changed by clicking the
Unit of measure box and selecting cm, ft, or in. Enter the Distance to
base, which is the distance from the SR50A’s wire mesh face to the
ground. SDI-12 Address defaults to 0. Enter the correct SDI-12 Address
for the SR50A if it has been changed from the factory-set default value.
Click on the Air temperature (Deg C) reference box and select T107_C.

SR50A-Series Sonic Ranging Sensors
4
5. After selecting the sensors, click Wiring Diagram to see how the sensor is
to be wired to the datalogger. The wiring diagram can be printed now or
after more sensors are added.
6. Select any other sensors you have, then finish the remaining Short Cut
steps to complete the program. The remaining steps are outlined in Short
Cut Help, which is accessed by clicking on Help | Contents |
Programming Steps.
7. If LoggerNet, PC200W, PC400, or RTDAQ is running on your PC, and the
PC to datalogger connection is active, you can click Finish in Short Cut
and you will be prompted to send the program just created to the
datalogger.
8. If the sensor is connected to the datalogger, as shown in the wiring
diagram in step 5, check the output of the sensor in the datalogger support
software data display to make sure it is making reasonable measurements.
5. Overview
The SR50A-series sensors measure the distance from the sensor to a target.
They determine the distance to a target by sending out ultrasonic pulses
(50 kHz) and listening for the returning echoes that are reflected from the
target. The time from transmissions to return of the echo is the basis for
obtaining the distance measurement.
Since the speed of sound in air varies with temperature, an independent
temperature measurement is required to compensate the distance reading for
these sensors. A simple calculation is applied to initial readings for this
purpose.
The SR50A-series sensors are capable of picking up small targets or targets
that are highly absorptive to sound, such as low density snow. They use a
unique echo-processing algorithm to help ensure measurement reliability. If
desired, these sensors can also output a data value indicative of measurement
quality.

SR50A-Series Sonic Ranging Sensors
5
The SR50A-series sensors meet the stringent requirements of snow depth
measurement that make them well suited for a variety of other applications.
The SR50A and SR50AH have rugged aluminum chassis that withstand many
environments, but the aluminum chassis is not suitable for marine (salty)
environments. The SR50A-316SS has a stainless-steel chassis with a parylene-
coated transducer head that allows the sensor to be used in marine or other
corrosive environments. The SR50AH includes a heater that prevents ice from
coating the transducer, but the heater increases the power consumption of the
sensor; see Appendix F, SR50AH Heater Operation (p. F-1), for more
information. Throughout this document SR50A will refer to all of the models
unless specified otherwise.
Sonic ranging sensors with integrated temperature sensors are also
available from Campbell Scientific; see the SR50AT, SR50AT-
316SS, and SR50ATH manual for more information.
SDI-12, RS-232, and RS-485 output options are available for measuring the
SR50A. The SR50A is factory configured as an SDI-12 sensor (address 0)
because Campbell dataloggers typically use the SDI-12 format. To use the
RS-232 or RS-485 format, three jumpers inside the SR50A need to be moved
(Section 9.1, Disassembly/Assembly Procedures (p. 15), and Appendix C,
Jumper Settings (p. C-1)). Refer to Appendix D, RS-232 and RS-485 Operation
(p. D-1), for more information.
6. Specifications
Features:
•Wide operating temperature range
•Compatible with Campbell Scientific CRBasic dataloggers:
CR200(X) series, CR300 series, CR6 series, CR800 series, CR1000,
CR3000, and CR5000
Power Requirements: 9 to 18 Vdc
Quiescent Power
Consumption (no heater)
SDI-12 Mode:< 1.0 mA
RS-232/RS-485 Modes: < 1.25 mA (≤ 9600 bps),
< 2.0 mA (> 9600 bps)
Active Power
Consumption (no heater): 250 mA typical
Measurement Time: Less than 1.0 s typical for RS-232 or
RS-485 measurements.
1.2 s typical for SDI-12 measurements.
Selectable Outputs: SDI-12 (version 1.3)
RS-232 (1200 to 38400 bps)
RS-485 (1200 to 38400 bps)
Measurement Range: 0.5 to 10 m (1.6 to 32.8 ft)
NOTE

SR50A-Series Sonic Ranging Sensors
6
Accuracy: ±1 cm (±0.4 in) or 0.4% of distance to
target, whichever is greater.
Accuracy specification excludes errors in
the temperature compensation. An external
temperature compensation is required for
the SR50A.
Resolution: 0.25 mm (0.01 in)
Required Beam Angle Clearance: 30°
Operating Temperature Range: –45 to 50 °C
Maximum Cable Length: SDI-12 60 m (196.9 ft)
RS-232 (9600 bps or less) 30 m (98.4 ft)
RS-485 300 m (984.3 ft)1
Cable Type: 4 conductor, 2-twisted pair, 22 awg,
Santoprene jacket
Chassis Types: Aluminum or 316L stainless steel
Sensor Length:10.1 cm (4 in)
Sensor Diameter:7.6 cm (3 in)
Sensor Weight (no cable)
Aluminum Chassis:0.4 kg (0.88 lb)
Stainless-Steel Chassis:0.795 kg (1.75 lb)
Cable Weight (15 ft): 0.25 kg (0.55 lb)
IP Rating
Electrical Housing: IP67
Transducer: IP64
Compliance: This device complies with Part 15 of the
USA Federal Communications
Commission (FCC) Rules. Operation in
the USA is subject to the following two
conditions:
1. This device may not cause harmful
interference.
2. This device must accept any
interference received, including
interference that may cause undesired
operation.
View the EU Declaration of Conformity at
•www.campbellsci.com/sr50a
•www.campbellsci.com/sr50a-316ss
•www.campbellsci.com/sr50ah
1Power supply must not drop below 11.0 V or heavier gage wire is required.

SR50A-Series Sonic Ranging Sensors
7
7. Installation
If you are programming your datalogger with Short Cut, skip Section 7.2,
SDI-12 Wiring (p. 10), and Section 7.3, SDI-12 Programming (p. 10). Short Cut
does this work for you. See Section 4, QuickStart (p. 2), for a Short Cut tutorial.
If not using SDI-12, refer to Appendix D, RS-232 and RS-485 Operation (p. D-1),
for wiring and programming information.
7.1 Sensor Mounting
7.1.1 Beam Angle
When mounting the SR50A, the sensor’s beam angle needs to be considered.
Mount the SR50A perpendicular to the intended target surface. The SR50A has
a beam angle of approximately 30 degrees. This means that objects outside this
30-degree beam will not be detected nor interfere with the intended target. Any
unwanted target must be outside the 30-degree beam angle.
Determine the required clearance for the beam angle using the following
formula and FIGURE 7-1.
Clearance Radius formula:
( )
CONE
0.=
CONE
heightradius
268
Where,
CONEheight = the distance to base (Section 7.1.2.1, Reference Point (p. 8))
CONEradius = clearance radius in the same measurement units as the CONEheight
FIGURE 7-1. Beam Angle Clearance
7.1.2 Mounting Height
Mount the SR50A so that the face of the transducer is at least 50 cm (19.7 in)
away from the target. However, mounting the sensor too far from the target can
increase the absolute error increases. For example, if your sensor is measuring
snow depth in an area that will likely not exceed 1.25 m (4.1 ft) then a good

SR50A-Series Sonic Ranging Sensors
8
height to mount the sensor will be 1.75 to 2.0 m (5.74 to 6.56 ft). Mounting the
sensor at a 4 m (13.1 ft) height can result in larger snow depth errors.
7.1.2.1 Reference Point
The front grill on the ultrasonic transducer is used for the reference for the
distance values. Because of the difficulty of measuring from the grill, most
users measure the distance from the target to the outer edge of the plastic
transducer housing (FIGURE 7-2), and then add 8 mm (0.3 in) to the measured
distance.
FIGURE 7-2. Distance from Edge of Transducer Housing to Grill
7.1.3 Mounting Options
To achieve an unobstructed view for the SR50A’s beam, the SR50A is
typically mounted to a tripod mast, tower leg, or user-supplied pole using the
CM206 6-ft crossarm or a pipe with a 1-inch to 1.75-inch outer diameter. The
19517 mounting kit attaches directly to the crossarm or pipe. FIGURE 7-3 and
FIGURE 7-4 show a couple of angles of the SR50A mounted to a crossarm
using the 19517. A U-bolt mounts the bracket to the crossarm and two screws
fasten the SR50A to the bracket.
The 19484 mounting stem (FIGURE 7-5) attaches to the crossarm using the
17953 Nu-Rail fitting (FIGURE 7-6), CM220 right-angle mount, CM230
adjustable-angle mount, or CM230XL extended adjustable-angle mount. Use
the CM230 or CM230XL if the surface is at an angle.

SR50A-Series Sonic Ranging Sensors
9
FIGURE 7-3. SR50A Mounted to a Crossarm via the 19517 Mounting
Kit
FIGURE 7-4. Another Angle of the 19517 Mounting Kit
FIGURE 7-5. SR50A Mounted to a 19484 Mounting Stem

SR50A-Series Sonic Ranging Sensors
10
FIGURE 7-6. SR50A-316SS Mounted to a Crossarm with the 19484
and Nu-Rail Fitting
7.2 SDI-12 Wiring
Power down your system before wiring the SR50A. Never
operate the sensor with the shield wire disconnected. The
shield wire plays an important role in noise emissions and
susceptibility as well as transient protection.
TABLE 7-1. Wire Color, Function, and Datalogger Connection
Wire Color Wire Function Datalogger Connection Terminal
Black Power Ground G
Red Power 12V
Green SDI-12 signal Control Port1or U configured for SDI-122
White Ground G
Clear Shield G
1Dedicated SDI-12 port on CR5000
2Uchannels are automatically configured by the measurement instruction.
To use more than one probe per datalogger, either connect the different sensors
to different terminals on the datalogger or change the SDI-12 addresses of the
sensors and wire them to the same terminal. Using the SDI-12 address reduces
the use of ports on the datalogger and allows sensors to be connected in a
daisy-chain that can minimize cable runs in some applications.
7.3 SDI-12 Programming
Short Cut is the best source for up-to-date datalogger programming code.
Programming code is needed when:
•Creating a program for a new datalogger installation
•Adding sensors to an existing datalogger program
CAUTION