RST Instruments RSTAR L900 Series User manual

RST INSTRUMENTS LTD.
11545 Kingston St.,
Maple Ridge, BC
CANADA V2X 0Z5
SALES + SERVICE + MANUFACTURING:
604 540 1100 |[e-mail]
TOLL FREE (USA & Canada) |1-800-665-5599
www.rstinstruments.com
All efforts have been made to ensure the accuracy and
completeness of the information contained in this document. RST
Instruments Ltd reserves the right to change the information at any
time and assumes no liability for its accuracy.
Copyright © 2020. RST Instruments Ltd. All rights reserved.
Document Number: ELM0077I
Release Date: July 2, 2020
L900 RSTAR Array Radio
Series System
Instruction Manual

L900 RSTAR Array Radio Series System
Instruction Manual
ELM0077I
RST Instruments Ltd.
Page ii
REVISION HISTORY
Rev.
Revision History
Date
Prepared By
Approved By
G
Updated URL for software updates,
added Revision Table, updated page
numbers, stand-alone data logger to
RSTAR conversion instructions removed,
updated battery information.
2019-Aug-21
MP
CJ
H
References to Table B-2 replaced with
references to Table A-1; configuration
codes for DT2485 10 Channel and
DT2485 40 Channel loggers updated to
0x81 and 0x85, respectively, and GAA
added to table; CE, WEEE, and Anatel
logos added.
2019-Dec-05
MP
CJ
I
DTSAA added to Table A-1, updated link
in 3.1.1.
2020-Jul-02
JT
AB

L900 RSTAR Array Radio Series System
Instruction Manual
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RST Instruments Ltd.
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TABLE OF CONTENTS
1 INTRODUCTION............................................................................................................1
1.1 Overview...........................................................................................................1
1.2 RSTAR Communications Principles..................................................................1
2 SAFETY ......................................................................................................................2
2.1 Battery ..............................................................................................................2
3 INSTALLATION.............................................................................................................3
3.1 Software Installation..........................................................................................3
3.1.1 Installing Node Logger Host Software.....................................................3
3.1.2 Installing FlexDAQ Hub Logger Host Software........................................3
3.2 Configuring LoggerNet™ Software....................................................................3
3.3 Commissioning RSTAR Field Data loggers.......................................................6
3.3.1 FlexDAQ Hub Data Logger Installation ...................................................6
3.3.2 Node Data Loggers Installation...............................................................6
3.3.3 Antenna Installation ................................................................................6
3.3.4 Assessing Radio Link Quality and Deployment.......................................7
4 OPERATION ................................................................................................................8
4.1 FlexDAQ RSTAR Data......................................................................................8
4.1.1 Retrieving Data Table from the FlexDAQ Hub Logger.............................8
4.1.2 RSTAR Sensor Data Table and Diagnostic Data Table...........................8
4.1.3 File Locations..........................................................................................9
4.1.4 Automatic Data Collection from FlexDAQ Hub Logger............................9
4.1.5 Custom Data Tables.............................................................................10
4.1.6 Addition of Node Loggers......................................................................10
4.2 Setting the RSTAR Measurement Interval.......................................................10
5 MAINTENANCE ..........................................................................................................11
6 SERVICE AND REPAIR................................................................................................11
APPENDIX A RTU COMMUNICATIONS ..............................................................................12
Power Requirements...............................................................................................12
Communication Ports ..............................................................................................12
RTU Communications for Network Read Sequence ................................................12
Setting the Current Time in the RTU........................................................................13
Reading the Current Time in the RTU......................................................................13
Reading the DT Loggers sensor timestamp.............................................................13
Setting the Network Read Interval ...........................................................................13
Determine RSTAR Listening State...........................................................................14
Retrieving Data from the RTU..................................................................................14
Acknowledging Data Transmission from RTU..........................................................15
APPENDIX B EXAMPLE CRBASIC CODE ..........................................................................16
Configuring the Number and Order of Node Loggers in RTU...................................17
Reading the RTU Radio Settings.............................................................................18

L900 RSTAR Array Radio Series System
Instruction Manual
ELM0077I
RST Instruments Ltd.
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LIST OF FIGURES
Figure 1-1 RSTAR Configured Data Loggers (Left) and RTU Hub (Right)..................................1
Figure 3-1 LoggerNet™Backup Screen.....................................................................................4
Figure 3-2 Installing the USB Drivers within LoggerNet™..........................................................5
Figure 3-3 Correct Antenna Orientation......................................................................................7
Figure 4-1 Example Sensor Data File for RSTAR Network with Two DT2011B Data
Loggers ...............................................................................................................8
LIST OF TABLES
Table 4-1 Diagnostic Data File Definitions..................................................................................9
Table A-1 Modbus Addresses for Different Logger Types........................................................15

L900 RSTAR Array Radio Series System
Instruction Manual
ELM0077I
RST Instruments Ltd.
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1 INTRODUCTION
FIGURE 1-1 RSTAR CONFIGURED DATA LOGGERS (LEFT)AND RTU HUB (RIGHT)
1.1 OVERVIEW
The RSTAR Array Radio Series System is a communications system that enables
wireless data acquisition from RST DT series data loggers. DT series data loggers
(Node Loggers) equipped with L900 radio kits wirelessly transmits sensor
measurements to an L900 Remote Terminal Unit (RTU). Refer to Figure 1-1.
The RTU stores the last readings sent from all Node Loggers and relays the
information over RS-232 or USB communications. The RTU also controls the reading
interval of Node Loggers and synchronises the clocks of all the Node Loggers.
The RTU will only store the most recent readings from the Node Loggers. When
purchased as part of a FlexDAQ Hub logger, Node Logger data is automatically
transferred and stored in the Hub Logger each time the network takes a reading.
Sensor data is stored in three locations: the Node Logger, the Hub Logger, and the
base station computer.
1.2 RSTAR COMMUNICATIONS PRINCIPLES
RSTAR networks are star type. Node data loggers send and receive data from only
one Hub RTU.

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All Node Loggers in the network will have the same reading interval and
synchronized clocks. All Node Loggers will simultaneously read their sensors when
scheduled to take a reading and will transmit their data to the Hub RTU over the next
1 to 2 minutes. The Node Logger clocks will be updated and any change in reading
interval will be implemented as they transmit their data.
The Hub Logger (often a Campbell Scientific data logger) will request data from the
Hub RTU once the Hub RTU has finished receiving data from the Node Loggers.
2 SAFETY
•Use the provided antenna only.
CAUTION: AVOID POWERLINES WHEN INSTALLING THE ANTENNAS.
•Observe grounding rules when installing Hub Loggers that are connected to line
power.
•Do not short or reverse the polarity of the Hub Logger battery. The battery may
leak lead and strong sulfuric acid if improperly handled.
WARNING: SHORTING OR REVERSING THE POLARITY OF THE HUB LOGGER BATTERY
MAY CAUSE LEAD AND STRONG SULFURIC ACID TO LEAK IF IMPROPERLY HANDLED.
•Never bypass the provided fuses when powering the Hub Logger.
2.1 BATTERY
3.6 V lithium-thionyl chloride batteries are recommended for use with any data
logger. Standard batteries (defined as SAFT LSH 20 D-cell, or equivalent) are used
for any logger with a wireless option (DT Link or RSTAR). Wireless connections will
not work with other lower current batteries.
More information regarding batteries and battery life can be found in the instruction
manuals for individual data loggers and in the DT Logger Host instruction manual
(ELM0080).
CAUTION:
DO NOT ATTEMPT TO RECHARGE THE BATTERY.
DO NOT REPLACE THE BATTERY WITH AN ALKALINE OR ZINC-CARBON BATTERY.
REMOVE STANDARD BATTERIES PRIOR TO SHIPPING DATA LOGGERS.

L900 RSTAR Array Radio Series System
Instruction Manual
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RST Instruments Ltd.
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3 INSTALLATION
3.1 SOFTWARE INSTALLATION
3.1.1 Installing Node Logger Host Software
1DT Logger Host software can be found on the RST website at:
https://rstinstruments.com/software-downloads/. Navigate to the website and
select the appropriate data logger.
2Follow the on-screen instructions. The default directory is:
C:\Program Files\RST Instruments\DT Logger Host\
The drivers will install automatically. Refer to RST Instruments Manual ELM0080
if the drivers do not install.
3.1.2 Installing FlexDAQ Hub Logger Host Software
1Insert the supplied LoggerNet™ DVD into the computer’s DVD drive. The disk
contains an auto-run feature.
2Click 'Install LoggerNet' when prompted. Follow the on-screen instructions.
3.2 CONFIGURING LOGGERNET™SOFTWARE
1Insert the provided data logger setup USB drive.
2Open LoggerNet™. Select the Main section and open the 'Setup' application.
3Ensure that the application is in 'Standard mode' by clicking on the 'Std View'
button located at the upper right corner of the application window. The
application is already in Standard mode should the button reads 'EZ View' as
seen in Figure 3-1.
4Select 'Backup' from the toolbar. Select 'Restore Network…'. Refer to Figure 3-1.

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FIGURE 3-1 LOGGERNET™BACKUP SCREEN
5Use the file dialog to select the '.bkp' file located on the USB drive and follow the
on-screen instructions. The configuration to communicate with the FlexDAQ
logger will be loaded.
6Click 'Apply' in the bottom left corner to save the settings.
7Select the Com Port from the top of the network tree within the 'Entire Network'
panel if connecting to the logger or base station radio over USB. Refer to Figure
3-2.
8Click the 'Install USB Driver' button on the Hardware panel. Choose the
appropriate interface from the resulting dialog. Refer to Figure 3-2.

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FIGURE 3-2 INSTALLING THE USB DRIVERS WITHIN LOGGERNET™
9Connect the logger or base station radio to the PC using the USB port. Wait for
the device to be recognized.
10 Select the appropriate port from the 'ComPort Connection' drop-down menu of
the Hardware panel.
11 Click 'Apply' to save the settings.
12 Select the ‘Connect’ application from the ‘Main’ section within the LoggerNet™
launch window.
13 Click the 'Connect' button. The data logger should respond within 30 seconds
and the connect button will show as connected.
14 Click the 'Set' button in the Clocks panel once successfully connected. All Node
loggers will inherit the Hub Logger clock’s time.
NOTE: THE DATA LOGGER MAY BE CONNECTED OVER CELLULAR MODEM BY
POWERING UP THE LOGGER AND ALLOWING THE MODEM TO CONNECT TO THE
NEAREST CELLULAR PHONE TOWER.THIS PROCESS MAY TAKE UP TO 4
MINUTES.THE NETWORK AND SIGNAL LIGHTS ON THE MODEM WILL STOP
BLINKING AND TURN GREEN.OMIT STEPS 7THROUGH 9ONCE CONNECTED TO
THE CELL TOWER.LOGGERNET™SETUP CAN BE VERIFIED WITH STEPS 10
THROUGH 12.

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3.3 COMMISSIONING RSTAR FIELD DATA LOGGERS
3.3.1 FlexDAQ Hub Data Logger Installation
•It is strongly recommended to commission and install the FlexDAQ Hub data
logger prior to installing Node Loggers.
•Choose a central location within line of sight of all Node Loggers when selecting
a location for the FlexDAQ Hub data logger. The location should be as elevated
as possible. It is possible to connect to Node Loggers over shorter distances that
are not visible from the Hub antenna; however, signal will be reduced, especially
if vegetation is present.
•Avoid installing the FlexDAQ Hub data logger near the edge of bodies of water if
possible. Multi-path interference can reduce signal quality.
3.3.2 Node Data Loggers Installation
•Consult RST Instruments Manual ELM0089 for RST Instruments DT series data
logger installation instructions.
•Antenna elevation will significantly improve radio link quality. Plan the Node
Logger installations accordingly. Antennas at ankle height receive approximately
an order of magnitude less signal than an antenna at waist height. The logger will
also be subject to inundation by snow in many locations.
•Consider using a pole mounted directional antenna for Node Loggers with poor
line of sight or long distances to their Hub Loggers.
•Consider using a secondary enclosure as a pre-engineered solution for antenna
elevation and additional protection against vandalism and wildlife. Contact RST
Instruments about Data Logger Enclosures for more details.
CAUTION: DT SERIES DATA LOGGERS SHOULD NEVER BE SUBMERGED OR
INSTALLED IN A LOCATION THAT CAN BE FLOODED.ANY FAILURE TO SEAL THE
ENCLOSURE AGAINST MOISTURE WILL VOID THE WARRANTY.
3.3.3 Antenna Installation
•All antenna coaxial cable connections should be finger-tight and torqued from as
close to the thread as possible. Take care to avoid cross-threading the
connectors.
•Ensure the antenna is oriented parallel to the Hub Omni antenna if using
standard 3 dBi 'Rubber Ducky' Omni Antennas. Refer to Figure 3-3.
•Ensure that the antenna body is pointed at the Hub Omni antenna and the
reflector elements are correctly polarized if using a direction Yagi-Uda antenna.
Refer to Figure 3-3.

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FIGURE 3-3 CORRECT ANTENNA ORIENTATION
NOTE: OMNI ANTENNAS PROVIDED BY RST INSTRUMENTS WILL BE VERTICALLY
POLARIZED.ANY NODE LOGGER ANTENNAS NOT ORIENTED IN THE SAME
DIRECTION WILL SUFFER A SIGNIFICANT SIGNAL PENALTY.
•Sealing the connections using Scotch® 130C Linerless Rubber Splicing Tape is
recommended, especially in cold or wet environments.
3.3.4 Assessing Radio Link Quality and Deployment
In the rare event of lost packets between RSTAR data loggers and an L900 RTU
HUB, RST has built-in software mechanisms that facilitate packet re-transmission for
robust communications.
Signal strength can be assessed in the field with an operational commissioned Hub
Logger when installing Node Loggers. The following instructions may also be used to
locate the optimal aiming of Yagi antennas.
1Connect the Node Logger to the computer via USB.
2Open the DT Logger Host software on the computer.
3Locate the 'Connections' tab. Select 'Wireless Settings'. Select ‘RSTAR Settings’
4Press 'Ping' to start a constant stream of signal quality requests from the RTU.
5The RSSI recorded at the Node Logger (Logger) and Hub (Base) will be
displayed. The strongest signal measurable by the radio module is 40. Missed
transmissions will begin to occur past 65-70. A returned value of 0 indicates no
response packet was received.
6Press 'Stop' to cease transmission once link quality has been optimized.
7Press the 'Sync' button to update the Node Logger’s clock, interval, and
transmission slot.

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Instruction Manual
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RST Instruments Ltd.
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4 OPERATION
4.1 FLEXDAQ RSTAR DATA
4.1.1 Retrieving Data Table from the FlexDAQ Hub Logger
Connect to the Hub logger using the LoggerNet™ Connect application and click
'Collect Now' to retrieve the data.
Two data tables will be downloaded for each Node Logger type in the network. One
file will contain sensor data. The other will contain the logger and RSTAR network
diagnostic data.
4.1.2 RSTAR Sensor Data Table and Diagnostic Data Table
Each logger table will record the battery voltage and temperature of the Hub Logger
as the first two data fields of the table. Subsequent columns contain the sensor or
diagnostic data.
FIGURE 4-1 EXAMPLE SENSOR DATA FILE FOR RSTAR NETWORK WITH TWO DT2011B
DATA LOGGERS
For example, the column heading 'DT11-2_Ch-1' in Figure 4-1 is the first channel of
the second data logger in the network. A reading of 'NAN' indicates that data was not
received at the RTU from the Node Logger.
Information about each transmission from each logger is stored within the diagnostic
data file. The definitions for each field type are defined in Table 4-1.
The data logger prefix in the field name (E.G., ‘DT11-2’) is shared between the
sensor data table and the diagnostic data table. This relationship is useful for
determining the origin of sensor data.
For example, to find the origin logger of the data recorded in the ‘DT11-2_Ch-1’
column, simply find the serial number recorded in the ‘DT11-2_SerianNumber’ field
of the diagnostic data table.
Node loggers will be in ascending serial number order in the sensor data and
diagnostic data tables if no modifications have been made to the RSTAR network.

L900 RSTAR Array Radio Series System
Instruction Manual
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RST Instruments Ltd.
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TABLE 4-1 DIAGNOSTIC DATA FILE DEFINITIONS
Field
Definition
SerialNumber
Serial number displayed on the lid of the Node Logger.
BatteryVoltage
Battery voltage of the primary cell of the node Data logger. Note that the
lithium metal battery voltage is not correlated with battery life remaining.
More information can be found in the manual of the corresponding data
logger.
Temperature
This field is the temperature in degrees Celsius of the data logger. This
does not refer to the thermistor of sensors being read by the data logger.
RRSIL
This refers to the signal strength of the response packet received at the
logger node data logger.
RSSIB
This refers to the signal strength of the packet received at the RTU.
RxTime
The time from the beginning of the RSTAR transmit window that the
logger’s data packet was received.
TxRxStatus
This is the status code used to diagnose radio errors.
ReTxCount
This refers to the number of times the logger has failed to send a data
packet. Retries are usually caused by lack of signal or noise sources
near the Hub or Node Logger. If this field is increasing steadily, a higher
gain antenna may be required.
Status
Diagnostic code for the Node logger’s program status.
Open
Reserved for future use.
4.1.3 File Locations
LoggerNet™ saves downloaded tables in the C:\Campbellsci\LoggerNet directory
by default. This can be changed in the 'Setup' application. Select the FlexDAQ Hub
logger in the Network tree and navigate to the Data Files Tab.
Be aware that the '*.dat' files generated by LoggerNet™ are added to on subsequent
data downloads. The files in the C:\Campbellsci\LoggerNet directory should only
be copied and never be edited or renamed.
NOTE: THE DOWNLOAD LOCATION WILL RESET TO THE
‘C:\CAMPBELLSCI\LOGGERNET’DIRECTORY IF THE TABLES ARE EVER
CHANGED WITHIN THE FLEXDAQ HUB LOGGER BY UPLOADING A NEW
PROGRAM.
4.1.4 Automatic Data Collection from FlexDAQ Hub Logger
Automatic data retrieval can be set up in the LoggerNet™ 'Setup' Application for
FlexDAQ Hub Loggers connected to cellular modems or radio infrastructure.

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RST Instruments Ltd.
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1Select the FlexDAQ Hub logger in the Network tree and navigate to the Schedule
Tab.
2Check the box title 'Scheduled Collection Enabled'.
3Change the base Time to '12:01:00'.
4Change the collection Interval to the minimum interval you plan to use for the
RSTAR network.
5Set the Primary Retry interval to 1 minute.
6Set the number of Primary retries to 5.
7Deselect the 'Secondary Retry Interval Enabled' box.
8Apply the settings.
NOTE: IF THE HUB FLEXDAQ LOGGER RUNS LONG ENOUGH WITHOUT
DOWNLOADING ITS DATA,THE FLEXDAQ LOGGER MEMORY WILL WRAP AND
DATA WILL NEED TO BE RETRIEVED FROM THE NODE DATA LOGGERS TO FILL
IN THE GAP.
4.1.5 Custom Data Tables
Custom solutions are possible for data structures. Contact RST Instruments for
details.
4.1.6 Addition of Node Loggers
Contact RST regarding expanding the number of Node Loggers in an RSTAR
network.
4.2 SETTING THE RSTAR MEASUREMENT INTERVAL
Network scan rates can be any period that divides evenly into 24 hours. For
example, a scan rate of 60 minutes is acceptable but a scan rate of 61 minutes will
result in an error.
Node data loggers will take sensor readings at each reading period starting at
midnight. For example, if the interval is set to 6 hours, readings will be taken at
0000h, 0600h, 1200h, and 1800h.
The network scan rate cannot be set to less than 1 minutes or the listening window
for transmit and retransmit of Node Loggers, whichever is longer.
FlexDAQ Hub loggers are configured with user selectable network intervals. The
following steps outline how to view or modify the RSTAR reading interval:

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1Open the LoggerNet™ software and open the 'Connect' application from the
Main menu.
2Connect to the FlexDAQ Hub logger.
3Open the 'Ports & Flags' interface.
4Highlight an empty cell and click the 'Add…' button.
5Locate the 'Public' Table. Select 'rstarMin_10' through 'rstarHr_12'. Click the
'Paste' button.
6The current reading interval will be highlighted. Change the reading interval by
clicking the desired indicator and deselecting the current interval’s illuminated
green indicator. This process may take 10 to 20 seconds and the indicator will be
grey while the logger receives and confirms the commands sent by LoggerNet™.
Contact RST Instruments if a different measurement interval is needed.
NOTE: THE QUIESCENT CURRENT DRAW OF THE DT SERIES DATA LOGGERS IS
EXTREMELY LOW.LITHIUM-THIONYL CHLORIDE BATTERIES LOSE VERY LITTLE
CHARGE OVER TIME.THE BATTERY LIFE OF THE DT SERIES DATA LOGGERS IS
DETERMINED BY HOW OFTEN SENSORS ARE READ.MORE INFORMATION CAN
BE FOUND IN THE MANUAL FOR THE CORRESPONDING DATA LOGGER AND IN
THE DT LOGGER HOST INSTRUCTION MANUAL (ELM0080).
5 MAINTENANCE
Refer to RST Instruments Manual ELM0088 for desiccant and battery replacement
information for individual DT series data loggers.
6 SERVICE AND REPAIR
The product contains no user-serviceable parts. Contact RST for product service or
repair not covered in this manual.

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RTU COMMUNICATIONS
The following section provides detailed instructions about communicating with the
L900 RTU. The RTU Host software may also be used for some simple tasks. Please
consult the RTU Host Instruction Manual (ELM0098) for further information.
POWER REQUIREMENTS
The L900 RTU can be powered through the USB or by using the 12 V and G
terminals. The RTU will consume approximately 25mA of current under normal
operations.
COMMUNICATION PORTS
The L900 RTU can communicate over either the USB or the Tx, Rx, and G terminals
on the RS-232. Both ports will echo received transmissions.
Communications are echoed between both ports. For example, communications
received on the Rx terminal of the RS-232 port will be echoed on the USB and
RS-232 ports. The response of the RTU when it requests for data will be sent to both
the USB and RS-232 ports.
The RS-232 port uses a baud rate of 115200 bps, 8 data bits, no parity, and 1 stop
bit.
The USB port uses a baud rate of 921600 bps, 8 data bits, no parity, and 1 stop bit.
NOTE: The USB port has a 2-character buffer which can be exceeded in the case of
the processor being used for other tasks. An inter-character delay of 2 ms is
recommended.
All communications except for MODBUS slave use the base ASCII character set.
Strings sent to the RTU by ASCII communications are only interpreted by the RTU
processor when the carriage return character is sent (ASCII character 13 - <CR>
henceforth). String use a space separator (ASCII character 32 - ˽henceforth).
RTU COMMUNICATIONS FOR NETWORK READ SEQUENCE
Communications between the RTU and Hub data logger should follow the sequence
below for the reading interval time T. Refer to Appendix B.
1At (T –00:01:00), the Hub data logger should update the RTU’s current
time. This time will be shared with all Node Logger when they send their data.
2At (T + 00:00:10), the Hub logger will request the RSTAR listening state.
The RTU response indicates whether or not the RTU is still waiting for Node data
logger Transmissions. If this response is not received, the data logger should
wait an appropriate interval before requesting the listening state again. Standard
programs use 10 seconds between requests.

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3At (T + n * 00:00:10), when the RTU responds that it has received all data
from Node Loggers, the Hub will request the Node logger sensor reading
timestamp.
4At (T + n * 00:00:10), Node Logger data is requested and transmitted from
the Hub RTU via MODBUS master by the Hub data logger.
5At (T + n * 00:00:10), once all node data has been received by the Hub
Logger, the Hub Logger acknowledges the data transmission and clears the RTU
memory for the next node sensor reading.
SETTING THE CURRENT TIME IN THE RTU
Use the following command to set the current time in the RTU:
‘WT˽<Y>˽<M>˽<D>˽<h>˽<m>˽<s><CR>’ where <Y> is the year, <M> is the month,
<D> is the day of month, <h> is the hour (midnight is 0), <m> are the minutes, and
<s> are the second.
For example ‘WT˽2010˽11˽12˽13˽14˽15<CR>’ would set the time to 1:14:15
PM, November 12th, 2010.
NOTE: THE REALTIME() FUNCTION IN CRBASIC WILL RETURN THE TIME AT THE
START OF THE SCAN INTERVAL AND NOT THE TIME WHEN THE FUNCTION WAS
CALLED.DELAYS AND PROCESSING TIME BEFORE THE TIME IS WRITTEN TO
THE RTU WILL RESULT IN AN OFFSET IN SEND TIME.
READING THE CURRENT TIME IN THE RTU
Use the following command to read the current time in the RTU:
‘RT<CR>’ where the order of returned date-time values is the same as write time
(‘WT’) command.
READING THE DT LOGGERS SENSOR TIMESTAMP
Use the following command to query the time when the DT loggers last read their
sensors:
‘DT<CR>’ where the order of returned date-time values is the same as write time
(‘WT’) command.
SETTING THE NETWORK READ INTERVAL
Use the following command to set the network read interval:
‘INTW˽<h>:<m>:<s><CR>’ where <h> are hours, <m> are the minutes, and <s>
are the second.

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DETERMINE RSTAR LISTENING STATE
Use the following command to determine the RSTAR listening state:
‘QT<CR>’
The RTU will respond with ‘,1,...’ Or ‘,0,…’ indicating outside or inside RSTAR
listening interval respectively.
This function can be used to make sure that all possible data is collected before
retrieving data from the RTU.
RETRIEVING DATA FROM THE RTU
MODBUS MASTER
Data for each DT logger type can be queried from the RTU using MODBUS function
4 (read coils). The MODBUS addresses for different logger types are summarized in
Table A-1.
For each logger of a requested type, the RTU will return 10 diagnostic fields, then the
sensor data. As an example, for a network of two DT2011B Node Loggers: the first
10 returned values will be diagnostic from the first Node DT2011B, the next two
channels will be sensor data from first Node DT2011B, the next 10 channels (13th
through 22nd inclusive) will be diagnostic data from the second Node DT2011B, and
the 23rd and 24th values will be the sensor data from the second Node DT2011B. See
Table 4-1 for the identities of each the diagnostic fields.
MODBUS MASTER IN CAMPBELL DATA LOGGERS
The Following is a general case use of the MODBUS master function for Campbell
Scientific Loggers:
‘ModbusMaster(<ModbusResultVar>,<ComPort>,115200,<Modbus
Address>,4,<TargetDataArray>,1,<totalChannels>,3,100)’
Contact RST if the total channels is greater than 720.

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TABLE A-1 MODBUS ADDRESSES FOR DIFFERENT LOGGER TYPES
Logger Type
MODBUS Address
Configuration
code
Channels per
Node Logger
DT2011B
128 (0x80)
0x11
12
DT2055B
129 (0x81)
0x55
20
DT2040
130 (0x82)
0x40
50
DT TILT
131 (0x83)
0x65
12
DT4205
132 (0x84)
0x42
20
DT2485 10 Channel
134 (0x86)
0x81
20
DT2485 40 Channel
133 (0x85)
0x85
50
DT2485 70 Channel
135 (0x87)
0x87
80
DT2485 100 Channel
136 (0x88)
0x80
110
DT2485 130 Channel
137 (0x89)
0x83
140
DT2485 170 Channel
138 (0x8A)
0x8F
180
DT2350
139 (0x8B)
0x35
20
DT2306
140 (0x8C)
0x23
*Contact RST
GAA
142 (0x8E)
0xAA
11
DTSAA
144 (0x90)
0x5A
*Variable
ACKNOWLEDGING DATA TRANSMISSION FROM RTU
Clear the current data to allow the next transmission interval to proceed once all data
has been correctly received from the RTU. Use the command:
‘ND˽1<CR>’

L900 RSTAR Array Radio Series System
Instruction Manual
ELM0077I
RST Instruments Ltd.
Page 16
EXAMPLE CRBASIC CODE
The following program will assign sensor and diagnostic data from 2 DT2011B
Loggers to the DT11Data() array. The reading interval of the network is 10 minutes
and the RTU is wired to the C1/C2 Com port on a CR300™type data logger.
01 'Declare number of DT2011B loggers in RSTAR network
02 Const nDT2011B =2
03
04 'Declare variables
05 Public DT11Data(nDT2011B *12)
06 Public i,timeSendString as string *28,rstarTime(9)
07 Public RTUflag As String *16,parsedRTUflag(6)As String *10
08 Public rstarTimeString As String *32,modBusResult
09
10 BeginProg
11 Scan(1,Min,0,0)
12 If TimeIntoInterval(0,10,Min)Then 'Execute when RSTAR network begins gathering data at
the RTU
13
14 SerialOpen(Com1,115200,0,0,100)
15
16 RTUflag ="" 'Reset RTU flag to guard against failed query
17
18 For i =1To 30 'Try every 10 seconds for 5 minutes
19 Delay(0,10,Sec)
20 SerialOut(Com1,"QT"+CHR(13),"",0,10)'Query for RSTAR Listening State
21 SerialIn(RTUflag,Com1,50,0,100)
22 SplitStr(parsedRTUflag(1),RTUflag,",",1,0)'Parse response
23 SerialFlush(Com1)
24
25 If parsedRTUflag(1)=1Then 'Execute if RTU is no longer listening for Node logger
transmissions
26 Delay(0,500,mSec)
27 SerialOut(Com1,"DT"+CHR(13),"",0,100)'Ask RTU for date-time of last RSTAR
transmission
28 SerialIn(rstarTimeString,Com1,50,0,100)
29 Delay(0,500,mSec)
30 SerialFlush(Com1)
31 SerialClose(Com1)
32
33 ModbusMaster(modBusResult,Com1,115200,128,4,DT11Data(),1,nDT2011B *12,3,100)'Query
RTU for collected RSTAR data
34
35 SerialOpen(Com1,115200,0,0,100)
36 SerialFlush(Com1)
37 Delay(0,500,mSec)
38 SerialOut(Com1,"ND 1"+CHR(13),"",0,100)'Acknowledge data from RTU
39 SerialFlush(Com1)
40 SerialClose(Com1)
41 ExitFor
42 End If
43
44 Next i
45
46 Else If TimeIntoInterval(9,10,Min)Then 'Execute 1 minute before RSTAR network begins
gathering data at the RTU
47 SerialOpen(Com1,115200,0,0,100)
48 RealTime(rstarTime()) 'Get current time of CR300 logger
49 timeSendString ="WT " +rstarTime(1)+" "+rstarTime(2)+" "+rstarTime(3)+" "+
rstarTime(4)+" "+rstarTime(5)+" "+rstarTime(6)+""+rstarTime(7)+CHR(13)'Package
CR300 time into compatible format for RTU
50 SerialOut(Com1,timeSendString,"",0,100)'Send CR300 time to RTU
51 SerialFlush(Com1)
52 SerialClose(Com1)
53 End If
54 NextScan
55 EndProg