Xylem H-4161 User Manual

Model

H-4161

SDI-12 to 4-20mA Interface

Owner's Manual

Version 1.2

75 West 100 South, Logan, Utah 84321 Phone: [phone] Fax: [phone] Web: http://www.waterlog.com E-mail: [e-mail]

D E S I G N A N A L Y S I S A S S O C I A T E S , I N C .

75 West 100 South, Logan, Utah 84321 Phone: [phone] Fax: [phone] Web: http://www.waterlog.com E-mail: [e-mail]

D E S I G N A N A L Y S I S A S S O C I A T E S , I N C .

User Agreement/

W

ATER

1. NATURE OF THE PRODUCT

This agreement accompanies an interface module comprising firmware, circuitry and other electronic
equipment in an enclosed housing, and packaged together with written instructional materials. The
packaged electronic circuitry and instructional materials herein are collectively referred to as the
“PRODUCT.” The PRODUCT is made available from DESIGN ANALYSIS ASSOCIATES, INC., of
75 West 100 South, Logan, Utah 84321 (hereinafter referred to as “DESIGN ANALYSIS”), and contains
information and embodies technology that is confidential and proprietary to DESIGN ANALYSIS, and
the availability and use of the PRODUCT is extended to you, the USER, solely on the basis of the terms
of agreement which follow.

2. ACKNOWLEDGMENTS BY USER

Opening the package which encloses the accompanying PRODUCT indicates your acceptance of the
terms and conditions of this agreement and constitutes an acknowledgment by you of the confidential and
proprietary nature of the rights of DESIGN ANALYSIS in the PRODUCT.

3. DUTIES OF YOU, THE USER

In consideration for the access to and use of the PRODUCT extended to you by DESIGN ANALYSIS
and to protect the confidential and proprietary information of DESIGN ANALYSIS, USER agrees as
follows:

LOG® Warranty

(a) USER agrees that they will not remove from the exterior of the housing of the PRODUCT any

safety warnings or notices of proprietary interest placed thereon by DESIGN ANALYSIS.

(b) USER agrees that they shall not disassemble or otherwise reverse engineer the PRODUCT.

(c) USER agrees to treat the PRODUCT with the same degree of care as USER exercises in relation to

their own confidential and proprietary information.

4. TERM

USER may enjoy these rights only as long as their possession of the PRODUCT shall continue to be
rightful. These rights will cease if the PRODUCT is returned to DESIGN ANALYSIS under the terms of
any redemption offer, warranty, or money-back guarantee, or if USER transfers the PRODUCT to
another party on terms inconsistent with this agreement.

5. LIMITED WARRANTY
(b) What is Covered

DESIGN ANALYSIS warrants that for a period of twelve months from the time of purchase the
functions to be performed by the PRODUCT will be substantially in compliance with USER
documentation. DESIGN ANALYSIS also warrants that the PRODUCT will be free from
defects in materials and workmanship for a period of ONE YEAR from the date of purchase.

(b) What USER Must Do

If the product fails to satisfy the above warranty, USER must notify DESIGN ANALYSIS in
writing within the applicable period specified above and reasonably cooperate with the directions
they received from DESIGN ANALYSIS.

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User Agreement/W

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LOG® Warranty W-1

(c) What DESIGN ANALYSIS Will Do

DESIGN ANALYSIS will repair the PRODUCT or will endeavor to provide a replacement of
same within a reasonable period of time. In the event that DESIGN ANALYSIS is unable to
make the necessary repairs or replacement within a reasonable period of time, the original
purchase price will be refunded upon the return of the PRODUCT to DESIGN ANALYSIS.

(d) Limitations

(i) THE ENTIRE REMEDY FOR BREACH OF THIS LIMITED WARRANTY SHALL

BE LIMITED TO REPLACEMENT OF THE DEFECTIVE PRODUCT OR
REFUNDING OF THE PURCHASE PRICE, AS SET FORTH ABOVE. IN NO
EVENT WILL THE LIABILITY OF DESIGN ANALYSIS TO USER OR TO ANY
OTHER PARTY EXCEED THE ORIGINAL PURCHASE PRICE OF THE PRODUCT,
REGARDLESS OF THE FORM OF THE CLAIM.

(ii) EXCEPT FOR THE EXPRESS WARRANTIES ABOVE, DESIGN ANALYSIS

SPECIFICALLY DISCLAIMS ALL OTHER WARRANTIES, INCLUDING,
WITHOUT LIMITATION, ALL IMPLIED WARRANTIES OF MERCHANTABILITY
AND FITNESS FOR A PARTICULAR PURPOSE.

(iii) UNDER NO CIRCUMSTANCES WILL DESIGN ANALYSIS BE LIABLE FOR

SPECIAL, INCIDENTAL, CONSEQUENTIAL, INDIRECT, OR ANY OTHER
DAMAGES OR CLAIMS ARISING FROM THE USE OF THIS PRODUCT, THIS
INCLUDES LOSS OF PROFITS OR ANY OTHER COMMERCIAL DAMAGES,
EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. IN NO EVENT
WILL DESIGN ANALYSIS BE LIABLE FOR ANY CLAIMS, LIABILITY, OR
DAMAGES ARISING FROM MODIFICATION MADE THEREIN, OTHER THAN
BY DESIGN ANALYSIS.

(iv) THIS LIMITED WARRANTY GIVES USER SPECIFIC LEGAL RIGHTS. USER

MAY ALSO HAVE OTHER RIGHTS WHICH VARY FROM STATE TO STATE.
SOME STATES DO NOT ALLOW LIMITATIONS ON HOW LONG AN IMPLIED
WARRANTY LASTS OR THE EXCLUSION OF INCIDENTAL OR
CONSEQUENTIAL DAMAGES, SO THOSE LIMITATIONS OR EXCLUSIONS
MAY NOT APPLY.

6. GOVERNING LAW

This Agreement and its validity and interpretation shall be governed by the laws of the State of Utah,
notwithstanding any choice of law rules of Utah or any other state or jurisdiction.

W-2 User Agreement/W

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LOG® Warranty

H-4161

Chapter 1

Introduction

1.0 Introduction

The W

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LOG® H-4161 is a SDI-12 to two-wire 4-20mA interface module. The H-4161 can be

programmed to either monitor communications between a data logger and its attached sensors or to
initiate measurements by itself. The measurement data is scaled as needed and output to a precision two­wire 4-20mA current transmitter.

Figure 1 H-4161 SDI-12 to 4-20mA Interface

The “SDI-12 Serial-Digital Interface” is ideal for data logging applications with the following
requirements:

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Battery powered operation with minimal current drain

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Low system cost

The H-4161 has the following features:

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Precision 16-bit 4-20mA current output

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1000V output isolation from the SDI-12 bus

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Can monitor the SDI-12 bus for a specified sensor address and data parameter

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Can initiate measurements to an attached sensor

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Programmable “Max” and “Min” data set points for automatic data scaling

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Manual “set” of the 4-20mA output using an extended SDI-12 command

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Two SDI-12 ports

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Introduction 1-1

1.1 Description

The H-4161 includes a microprocessor, LCD display, 16-bit digital-to-analog converter, precision voltage
reference and a 4-20mA current transmitter. The SDI-12 and 4-20mA sections are isolated from each
other with a high voltage digital opto-coupler. Data collected from the SDI-12 bus is scaled by the
microprocessor into a 16-bit value and loaded into the digital-to-analog converter. The digital-to-analog
converter directly controls the current transmitter.

The H-4161 has two SDI-12 ports. The primary SDI-12 port provides data monitoring and
communication with the H-4161 device itself. When programmed to initiate measurements, the H-4161
makes measurements and collects the data from a sensor connected to the auxiliary SDI-12 port.

1.2 Display

The H-4161 has a 2-line x 16-character Liquid Crystal Display (LCD) which shows the current
measurement data. Line-1 displays the most recently captured SDI-12 data parameter. If the sensor
buffer is invalid (no data captured or the previous measurement failed) the message “no data” is shown
instead of a number. Line-2 displays the current setting of the 4-20mA output. Note: the mA value is the
desired loop current setting which the microprocessor loads into the digital to analog converter. If the 4­20 mA loop is open, or insufficient loop voltage is present the actual loop current may be zero or may not
match the value on the display.

SDI = xxx.xx ft ­Iout = xx.xx mA

The character on the right hand side of Line-1 is an activity “spinner”. Every time a measurement is
captured or initiated, the spinner changes (rotates). This indicator shows measurements are being made
even if the measurement data is static (not changing).

1.3 Connectors

The H-4161 has a 5-position connector for making +12V and SDI-12 connections. The primary SDI-12
terminal is connected to the data logger and it’s attached sensors. If the H-4161 is to initiate
measurements, the auxSDI-12 terminal is connected to the SDI-12 sensor to be monitored. The 2­position connector is for making connections to the 4-20mA loop.

1-2 Introduction

H-4161

1.4 Monitor SDI-12 Communications (Module Mode = 0)

During normal operation the data recorder sends commands to one or more SDI-12 sensors and
subsequently collects data from the sensors. As a “data monitor”, the H-4161 passively monitors the
communication between the data recorder and its SDI-12 sensors. The H-4161 waits for, and collects a
specified data parameter from a specified sensor. The data is scaled and used to update the H-4161's 4­20mA output. In this mode the H-4161 monitors, but does not transmit data to the SDI-12 bus. The data
recorder must initiate any sensor measurements.

The data recorder can also communicate with the H-4161 directly as a normal SDI-12 “sensor”. Using
extended SDI-12 commands, the data recorder/user can manually set the 4-20mA output, observe the last
data collected or configure the H-4161.

Figure 2 The H-4161 monitors the SDI-12 bus for a selected

parameter

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Introduction 1-3

1.3 Initiate Measurements (Module Mode = 1)

Applications often arise where is it desired to connect a SDI-12 sensor directly to a 4-20mA input device
such as a PLC without the use of a data logger. When programmed to initiate measurements, the H-4161
sends 0M! (or 0M1 to 0M9) commands to the sensor attached to the auxSDI-12 port and collects the
measurement data. The data is scaled and used to update the H-4161's 4-20mA output.

The Initiate Measurement mode also provides support for a hybrid architecture employing both a data
logger and PLC. Both the primary and auxSDI-12 ports can be used. For example, the following
illustration shows a dam equipped with sixteen SDI-12 gate position sensors (inclinometers). Each gate
is equipped with a H-4161 module which initiates measurements and sends 4-20mA data to the PLC. All
16 channels make simultaneous measurements. The radial architecture provides near real-time gate
position data to the PLC. The system also has a data logger which periodically collects the gate position
and other data on a timed schedule. The data logger sends “aM!” measurement commands to each H­4161 and collects the resulting data, channel-by-channel. The measurement data collected in response to
the “aM!” command will be the data from the most recent measurement made by the H-4161 to the
sensor on the auxSDI-12 port (no actual “measurement” is made). The H-4161 supports simultaneous
SDI-12 commands/responses on both the primary and auxSDI-12 ports. The data logger can collect gate
position data without disturbing any measurements currently in progress with the gate position sensors.

Figure 3 Example architecture with sixteen 4-20mA channels and a data logger

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1-4 Introduction

H-4161

Chapter 2

Installation And Maintenance

2.1 General Installation Recommendations

The enclosure and connectors are not weather tight. The H-4161 must be installed in a protected location
or a weather tight enclosure. The enclosure has a 5-terminal connector for making power and SDI-12
connections and a 2-terminal connector for connecting the 4-20mA output connections. The connectors
can be detached while making the connections.

Caution: Remove all power from the unit before making any connections.

Before beginning the installation take a minute to plan out your station grounding and wiring scheme.

2.2 Making Power and SDI-12 connections

Connect the +12V and GND terminals to a 12V power source. If the H-4161 is to be used to Monitor,
connect the primary SDI-12 data terminal to the SDI-12 bus between your data logger and its sensors. If
the H-4161 is to be used to Initiate, connect the auxSDI-12 terminal to the sensor to be monitored. The
sensor address of the sensor connected to the auxSDI-12 terminal must be “0" (this cannot be changed in
the H-4161). The sensor address must be set before connecting the sensor to the H-4161.

2.3 Making the 4-20mA connections

The H-4161 has a 2-wire “self powered” current loop transmitter. Current loop sensors output a current
rather than a voltage. The 4-20mA output will drive standard industrial telemetry and process control
instrumentation. Use shielded twisted-pair cable and take precautions to protect the wiring from noise
and interference. Your loop power source, loop receiver and the H-4161's output should all be connected
in series. The loop power supply must be sufficient to maintain 5.5V to 35V across the H-4161s output
terminals, in addition to whatever voltage is needed to maintain 20mA across the loop receiver and
interconnect wiring. The gauge station +12.0V SDI-12 power source will work if the resistance of your
loop receiver and wiring is less than 250 ohms.

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Make certain their is 5.5 to 35V across the 4-20mA output terminals.

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Make certain the H-4161 is receiving +12V power from the SDI-12 data bus.

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Use shielded, twisted-pair cables for the 4-20mA connections in noisy environments.

H-4161

Installation And Maintenance 2-1

Note:

The SDI-12 logic and the 4-20mA interface are isolated from each other by digital optical isolators. The
SDI-12 logic is powered from the +12V input terminal, the 4-20mA circuitry is self-powered from the 4­20mA loop. When the H-4161 is first powered up, the output current is set to 4.0mA. It remains at

4.0mA until the first successful data collection sequence. If the loop power is disconnected or is applied

after the SDI-12 side is powered up, the data in the digital-to-analog converter will be undefined. When
the loop power is restored, the 4-20mA output will be at an unknown value. Once a fresh SDI-12 data
collection is made the digital-to-analog converter will be loaded with new valid data.

2.4 Programming the H-4161

The H-4161 comes from the factory with the following settings:

H-4161 device address 0
Max setpoint: 20.00
Min setpoint: 4.00
Monitored Address: Z
Monitored Parameter: 1
AutoScan Command: 0 (0M!)
Module Mode: 0 (monitor)
Measurement Rate: 0 (seconds)

These setups are stored in Flash memory within the H-4161 and will not be lost if the power is removed.
The extended commands for changing these settings are described in detail in Chapter 3.

2.5 Programming the Sensor Address

The H-4161 comes from the factory with its sensor address set to “0". If more than one sensor is to be
connected to the SDI-12 bus, make certain each sensor has a unique sensor address, including any H­4161 modules. The H-4161 is not a traditional sensor and does not ‘make measurements”. However, to
facilitate programming the H-4161 it must have a unique address.

2.6 Programming the Max and Min data setpoints

Captured SDI-12 data is scaled into 4-20mA units using the programmable Max and Min data setpoints.
This feature makes it easy to setup the H-4161 for your application. For example, if you are monitoring
stream stage which could be up to 10 feet, program the Max setpoint to 10.00. Perhaps the stream never
falls below 5 feet and you would like to narrow the dynamic range of the 4-20mA output for more
resolution. In this case program the Min setpoint to 5.00. A captured SDI-12 data value of 5.00 will
produce a 4.0 mA output and data value of 10.00 will produce 20.0mA. Note if the stage rises above

10.0 feet the output will clamp at 20mA or if the stage falls below 5 feet the output will clamp at 4.0mA.

The extended commands to examine or change the Min and Max values are explained in Chapter 3.

2-2 Installation And Maintenance

H-4161

2.7 Programming the Module Mode setting

The H-4161 can either “monitor” SDI-12 communication between a data logger and its sensors, or
“initiate” measurements to a dedicated sensor connected to the auxSDI-12 terminal. The H-4161 comes
from the factory with Module Mode = 0 (monitor). The extended commands to examine or change the
Module Mode are explained in Chapter 3.

2.8 Programming the Monitored Address setting

As a data monitor, the H-4161 passively monitors communication between the data recorder and its SDI­12 sensors. The H-4161 waits for, and collects data from a specified sensor. The data recorder must
initiate any sensor measurements. The H-4161 comes from the factory with the Monitored Address = Z.
If you wish to monitor data from another sensor you must change the monitored address to the desired
value. This setting is not used if Module Mode = 1 (initiate). The extended commands to examine or
change the Monitored Address are explained in Chapter 3.

2.9 Programming the Monitored Parameter setting

Each SDI-12 sensor can make up to nine separate measurements or “parameters”. The data recorder
collects the measurement data using “aD0!” - “aD9!” commands. The Monitored Parameter setting
controls which of the nine data parameters is to be monitored by the H-4161. The H-4161 also monitors
the data sent in response to the new concurrent SDI-12 V1.2 “aR0" data collection commands. The H­4161 comes from the factory with Monitored Parameter = 1. This setting should work with most
sensors. The extended commands to examine or change the Monitored Parameter are explained in
Chapter 3.

2.10 Programming the AutoScan Command setting

When the Module Mode =1 (initiate), the H-4161 actively initiates measurements and collects the
response from the sensor attached to the auxSDI port. The H-4161 normally issues an “0M!” command
to the auxSDI port. If desired, the H-4161 can be programmed to issue other commands such as “0M1!”
(“0M1" to “0M9!”). The extended commands to examine or change the AutoScan Command are
explained in Chapter 3.

2.11 Programming the Measure Rate setting

When Module Mode = 1 (initiate), the H-4161 initiates measurements to the sensor attached to the
auxSDI port. The measurement interval is controlled by the Measure Rate setting. If the Measure Rate
is set to a value less than the time it take to make the actual measurement, measurements will be made
back-to-back, as fast as possible. The H-4161 comes from the factory with Measure Rate = 0 (seconds).
This setting is not used if Module Mode = 0 (monitor).

H-4161

Installation And Maintenance 2-3