1-Watt Spread Spectrum Data modem H-4271
Contents
1. Subroutine SDI Send Command RS232 int port int radio Description Send an SDI 12 command out the selected serial port This is an upper level routine that handles sending breaks and retries Inputs port com port 1 2 or 3 radio yes or no Changes the time outs and wakes up the radios Return char 0 error 0 ok sensor address int radio Port is in use for the menu or command mode so just return with an error default to no response each retry will cause a break on the H 4191 Turn on the RS232 drivers if a radio connection is selected then send radio preamble putcharX port 0xFF putcharX port 0xFF putcharX port OxFF putcharX port OxFF putcharX port 0xFF putcharX port 0xFF putcharX port 0xFF send the command printstringX port SDI Out buffer wait xx seconds for the command Use a little longer delay for the radio mode The delay is not exact as overhead extends the loop if radio Timeout 6500 else Timeout 1500 msdelay 12. if port 1 if COM1 LastChar Timeout 0 2 8 Installation And Maintenance It may take up to 4 to wake the remote 4191 the first few chars are lost because 4191 is waking up during first few chars 6 5 second delay between retries 1 5 second delay CR LF terminates the response WArERL G 4271 if port 2 if COM2_LastChar 0x0A CR LF terminates the response Timeout 0 if port 3 if COM3_LastChar 0x0A CR LF terminates the response Timeout 0 if Timeout Timeout while Timeout for i 0 i lt 50 i move response to SDI In Buffer getcharX port 0 amp Data Data Data amp Ox7F strip off parity bit SDI_In_buffer i Data save in SDI buffer if Data 0 break make sure in buffer is empty before leaving do it quick so we do not get the service request while getcharX port 0 amp C look for proper SDI 12 address and return it or return a NULL if SDI_In_buffer 0 gt Data SDI_In_buffer 0 else Data 0 if retry 4 ss Data Only send the radio beacon retry 2 amp amp Data on selected retries msdelay 2000 if radio if a radio connection is selected putcharX port putcharX port putcharX port msdelay 2000 wait for OK putcharX port A This command forces the putcharX port T radio to resend the b
3. bursts Make certain your wiring and battery is capable of supplying sufficient current 2 3 Data Connector The H 4271 has a standard 9 pin RS 232 connector and is a DCE modem device Connect the RS 232 port to the serial port of your personal computer or other host device with a standard 9 pin RS 232 cable No gender changes or null modem adapters are needed Program your host device for 9600 baud 8 bit no parity full duplex communication fe fose DTR Data Terminal Internally connected to Pin 4 Ready 7 CTS Input Clear To Send Connected to the GPI1 RTS pin of the 9Xstream module RTS Output Request To Send Connected to the GPO1 CTS output pin of the 9Xstream module WAT ERLOG H 4271 Installation And Maintenance 2 1 2 4 Power Mode Jumper The end plate has a 2 position power mode jumper marked Auto and Always On For most applications install the jumper in the Always On position See Chapter 1 rr 2 5 Connecting The Antenna Warning When operating at a 1 Watt power output observe a minimum separation of 2 feet 0 6m between radio modules Transmitting in close proximity of other modules can the damage the front end circuitry of the modules RF Exposure Warning This equipment is approved only for mobile and base station transmitting devices It is not tested for portable applications Antenna s used for this transmitter must be installed to provide a separation distance of at least 30c
4. 12 commands from the data logger are forwarded via the radios to the remote H 4191 When the remote data radio receives an inbound data packet it pulses the CTS input of the H 4191 which awakens the H 4191 in preparation to receive the inbound message When the H 4191 detects the character it transmits the contents of its buffer to the remote SDI 12 bus ina contiguous frame with proper parity and bus timing The H 4191 waits for and collects any sensor response and forwards it to the radio The sensor response is sent over the radios back to the data logger If one or more of the radio transmissions is lost or corrupted the data logger can retry the entire sequence as needed LOG H 4191 Model RS 232 to SDI 12 Interface S N 100 Rev A Input 9 to 16 Volts 9600 Baud RS 232 DCE is H 4191 RS 232 to SDI 12 Interface 1 4 Introduction War ER L G H 427 1 The H 4191 has an internal inactivity timer which keeps the module awake to process the service request and receive subsequent packets from the radio If both the RS 232 and SDI 12 ports become inactive and both CTS and RTS are not asserted for longer than 10 seconds the timer expires and the H 4191 enters its low power sleep mode The H 4191 examines the aTTTN lt CR gt lt LF gt sensor response initiated by an aM measure command and initializes a second keep awake timer to TTT 3 seconds This ensures the H 4191 will remain awake to process th
5. preprogrammed with certain configurations such as sleep amp sniff master sleep amp sniff slave or repeater If desired the user can change the transmit power or other settings depending on specific needs In general the factory preprogrammed modes configure the modems for point to multipoint communications Messages sent by the master are received by all of the slaves With this scheme no addressing is done by the radios themselves and the communication protocol must include an in band addressing protocol such as SDI 12 where only one slave will attempt to respond to a specific message The X CTU is a Windows based application designed to interact with the firmware files found on Digi s RF products and to provide a simple to use graphical user interface X CTU is designed to function with all Windows based computers running Microsoft Windows 98 SE and above X CTU can be downloaded from Digi s web site The 9XTend module can be configured using a terminal program and AT modem commands however the X CTU software is much more convenient In addition the X CTU software has support for testing the complete radio link as described in Chapter 2 1 5 Power Management The H 4271 is often used with remote solar powered water and meteorological monitoring stations Such applications however require special attention to power management Be aware the standby receive current of the H 4271 is 65mA and will require a very larg
6. radio for loopback operation by installing a DB9 connector with pins 2 amp 3 connected together The radio link is essentially a full duplex connection depending on the settings of your terminal program you may or may not be able to see what you are typing on your screen Test the radio link by typing characters and checking for the proper echoed response As you type the characters are transmitted to the remote station then re transmitted back to the local station and displayed on your screen Both up link and down link paths are tested at the same time A much more productive test is to use Digi s X CTU software utility To use this test select the Range Test menu and Start the test This automated test sends repeated packets and maintains a history of good and bad packets It shows the communications data and displays a real time reading of the percent of good packets War ERLOG H 427 1 Installation And Maintenance 2 7 2 9 Example Sleep amp Sniff Host Driver far char SDI Send Command RS232 int port t char Data char int Timeout int ay char buffer 50 char retry if port MainPort return 0 start of retry loop Data 0 retry SDIBreakRetry 1 A do EnableComPort port 9600 if radio AA
7. 16 6 ms 1 1200 x 10 8 3ms assures data will arrive in contiguous packets ATST 64 time before sleep inactivity timer 100 x 1 10 seconds ATHT 50 time to beacon 80 x 1 8 0 seconds ATLH 64 wakeup initializer beacon transmit time 100 x 0 1 10 0 seconds ATWR write setttings ATCN cancel AT mode 2 7 3 Sleep amp Sniff Slave lt CR gt activate AT mode ATRE restore defaults ATBD 3 9600 baud ATNB 0 no parity ATPL 4 I watt ATCD 0 GPO2 RxDat LED ATCS 1 assert RTS while receiving data ATSM 6 cyclic 4 0 second sleep ATDT DCAB set the networking address ATRO 10 packetization timeout 16 x 1 9600 x 10 16 6 ms 1 1200 x 10 8 3ms assures data will arrive in contiguous packets ATST 64 time before sleep inactivity timer 100 x 1 10 seconds ATWR write setttings ATCN cancel AT mode WATERLOG 11 4271 Installation And Maintenance 2 5 2 7 4 Repeater These settings configure the radio for repeater operation With repeaters sleep amp sniff will not work All radios in the network must be continually powered With these settings any radio can be a repeater master or a slave Each module must have a unique MY Source Address parameter These settings are for Broadcast communications each packet comes out every node exactly once Step 1 Program radio with custom modem settings lt CR gt ATRE ATBD 3 ATNB 0 ATPL 4 ATCD 0 ATCS 1 ATDT DCAB ATRN 1 ATPK 100 ATRB FF ATRO 10 ATMD 5 ATWR A
8. 32 transceiver remains continually powered 1 2 Introduction War ER L 6 1 4271 1 7 Point to Point By default the modems operate in a transparent mode The modems act as a serial line replacement If multiple modems are installed data transmitted by one modem is received by all of the other modems within range In this mode the standby receive power is 65mA typ This mode is often used with SCADA applications where AC power is available and power is not of concern 1 8 Sleep and Sniff Sleep amp Sniff is a power management scheme normally used for solar panel powered systems With Sleep amp Sniff one modem is configured as a Master and is connected to the data logger One or more modems are configured as Slaves and are connected to the remote sensing sites With Sleep amp Sniff both the master and slave station s normally operate in a low power state The slave stations periodically awaken and listen sniff for a beacon signal In this mode the slaves only draw 65mA for a few milliseconds every 4 seconds or so The Sleep amp Sniff interval is programmable depending on the desired power profile and system response time The Master is configured to awaken via serial port sleep when it detects an inbound message from the data logger The master prefixes the transmission with a beacon signal which is detectable by the slave modems After sending the beacon for a programmable period the master transmits the data packet The recom
9. Model H 4271 1 Watt Spread Spectrum Data modem WATERLOG SERIES Owner s Manual Version 1 0 DESIGN ANALYSIS ASSOCIATES INC 75 West 100 South Logan Utah 84321 Phone 435 753 2212 Fax 435 753 7669 Web http www waterlog com E mail waterlog waterlog com DESIGN ANALYSIS ASSOCIATES INC 75 West 100 South Logan Utah 84321 Phone 435 753 2212 Fax 435 753 7669 Web http www waterlog com E mail waterlog waterlog com User Agreement WATERLOG Warranty 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 propr
10. 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 j YA YAT ER LOG H 4271 User Agreement WATERLOG 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 CONSEOUENTIAL INDIRECT OR ANY OTHER DAMAGES OR CLAIMS ARISING FROM THE USE OF THIS PRODUCT THIS INCLUDES LOSS OF PROFITS OR A
11. NY 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 CONSEOUENTIAL 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 WATERLOG Warranty WAT ER LOG H 4271 Chapter 1 Introduction 1 0 Introduction The WATERLOG H 4271 is a I watt FHSS Frequency Hopping Spread Spectrum telemetry modem The modem transfers a standard asynchronous RS 232 serial data stream and operates within the ISM 900 MHz frequency band Two or more H 4271 modules are required one connected to the data recorder and one located at each remote site The radio link uses modern frequency hopping spread spectrum telemetry radios Spread spectrum technology is highly secure and has good interference immunity The radio operates in the license free 900 Mhz ISM Band eliminating the need for any FCC licensing Key features e Lo
12. TCN activate AT mode restore defaults 9600 baud no parity I watt GPO2 RxDat LED assert RTS while receiving data set the networking address delay slots repeaters may be in reach of each other max packet size 256 bytes packetization threshold 255 bytes packetization timeout 16 x 1 9600 x 10 16 6 ms 1 1200 x 10 8 3ms assures data will arrive in contiguous packets repeater write settings cancel AT mode Step 2 Set the MY address for each radio 2 6 Installation And Maintenance lt CR gt ATAM ATWR ATCN Activate the AT mode autoset the address write the new setting cancel AT mode 24rzzL 1H 4271 2 8 Testing and Troubleshooting You can test radio link by connecting a laptop computer to one radio and installing a loop back connector on the other radio With this configuration one person can test both up link and down link communication paths while aligning or testing the antennas Run a serial communications program such as Xtalk Hyperterminal or Simpleterm on the computer Connect the local radio to the laptop computer with a standard 9 pin RS 232 cable Make sure your computer or terminal is set for full duplex 9600 Baud If the Mode jumper is set to auto the communications program must assert the DSR input signal to the H 4271 to awaken it from sleep The radios have a female DB9 connector pin 2 is received data output and pin 3 is transmit data input Configure the remote
13. e service reguest When the service reguest actually arrives the keep awake timer is zeroed While the keep awake timer is running the H 4191 sends a null 00h to the radio once second to keep the radio link awake while waiting for the service request The data logger must discard the 00h characters When using a H 4191 SDI 12 gateway the data logger must prefix all messages with four or five OxFF characters to allow the H 4191 to awaken before the message payload arrives The H 4191 automatically discards OxFF characters such that they are not passed on to the SDI 12 sensor The radios used in this architecture are normally programmed for sleep amp sniff low power operation When properly configured the data logger radios and H 4191 module can provide a low power wireless SDI 12 bridge capable of performing retries 1 11 FCC Restrictions This equipment has been tested and found to comply with the limits for a Class B digital device pursuant to Part 15 of the FCC Rules These limits are designed to provide reasonable protection against harmful interference in a residential installation This equipment generates uses and can radiate radio frequency energy and if not installed and used in accordance with the instructions may cause harmful interference to radio communications However there is no guarantee that interference will not occur in a particular installation If this equipment does cause harmful interference to radio or televis
14. e solar panel if continually powered The 9XTend module features a Sleep amp Sniff low power mode which can be used to reduce the solar panel and gauge station battery requirements 1 6 Power Mode Jumper The end plate has a 2 position jumper marked Auto and Always On When the jumper is in the Auto position the transmitter power is controlled by the DSR input When DSR input pin 4 is de asserted the transmitter and RS 232 transceiver are completely powered off In this state the H 4271 is in its lowest power condition and only draws 260uA or so When the jumper is in the Always On position the internal power switch is forced to the ON state Normally the power switch is only used with a master station where the modem is connected directly to a data logger The data logger can use the DSR input to explicitly control the power state and can place the H 4271 in its lowest current state The Auto mode should not be used with a remote station in that the modem is continually powered off and would not be able to receive packets Alternatively the internal 9XTend module includes a pin sleep feature which is also controlled by the DSR input pin 4 With this configuration the jumper is set to Always On and the 9XTend module is programmed to do its own power management This configuration has the advantage of better response in that the 9XTend module does not need to do a cold power up each time On the other hand a disadvantage is that the RS 2
15. eacon putcharX port F to the remote radio putcharX port H now making this part of putcharX port the retry process putcharX port C putcharX port N putcharX port 0x0A putcharX port 0x0D msdelay 2000 wait for OK while getcharX port 0 amp c start with a clear buffer while retry ss Data return Data WAT ERLOG H 4271 Installation And Maintenance 2 9 2 10 Installation And Maintenance YAT ER LOG H 427 1 Radio Frequency Range Spread Spectrum Modulation Channel Capacity Transmission Power Receive Sensitivity Indoor Urban Range Outdoor RF line of sight Antenna Impedance Certifications Serial Port Type Data Rate Power Requirements Voltage Input Power Control 902 to 928 Mhz Frequency Hopping FSK 10 hop sequences share 50 frequencies 1mW 1Watt 110 dBm Up to 3000 900m Up to 14 miles w dipole antenna Up to 40 miles w high gain antenna 50 ohms FCC Part 15 247 RS 232 DCE 9600 bps 9 0 to 18 0 Volts DC Always on Sleep amp Sniff Host controlled via DSR Current 12 0V jumper auto Standby Receive Transmit 260uA 65 mA 450 mA Current 12 0V jumper always on Receive Transmit 60 mA 450 mA WATERLOG H 4271 SERIE Appendix A Specifications Environmental Operating Temperature 40 to 85 C Storage Temperature 40 to 85 C Humidity N
16. ecial RG8 connectors zL 1 427i aa ER E S 2 2 Installation And Maintenance 2 6 Words of Caution Successful operation can depend on may factors Multipath interference and other site specific problems can make a radio link unworkable After installation it is highly recommended to test the link with the Digi s X CTU software utility as explained at the end of this chapter When multipath conditions exist simply moving one of the antennas a few feet can make a difference In general use low loss antenna cable a high quality antenna and mount the antenna as high above the earth as possible 900MHz signals require line of sight operation and generally will not propagate around hills or other large obstructions A wise system integrator will perform a preliminary site test to see if the link is workable before permanently installing the eguipment e Even though the H 4271 operates in a low power mode the transmitter requires 500mA for short bursts Make certain your wiring and battery is capable of supplying sufficient current Keep the antenna cable as short as possible Use low loss antenna cable Install a lightening protection device on the antenna cable Connect the modem case to a good earth ground Protect any exposed antenna connectors from water and corrosion 2 7 Modem Configuration The following sections document the modem configurations for several specific applications available from the factory These settings can be ch
17. ecked or changed with either AT commands or with use of Digi s X CTU Windows based application as described in Chapter 1 General configuration notes e All radios are setup for 9600 baud e Set the destination address for all radios to the same unique value Design Analysis Associates uses ATDT DCBA e A master configured for Sleep amp Sniff is workable with a slave which is not configured with Sleep amp Sniff the slave ignores the beacon e Set ATCS 1 in the slave radios so RTS will awaken the H 4191 module when used Set ATCD 0 so the RxDat LED will work e The ATRO and ATMD commands have different settings between the 9Xstream and 9XTend models War ERLOG H 427 1 Installation And Maintenance 2 3 2 7 1 Generic works with the H424 transparent SDI 12 bridge lt CR gt ATRE ATBD ATNB ATPL ATCD ATCS ATSM ATDT ATWR ATCN WATERL G 4271 Of OW DCAB activate AT mode restore defaults 9600 baud no parity I watt GPO2 RxDat LED assert RTS while receiving data pin sleep via DSR input set the modem address write setttings cancel AT mode 2 4 Installation And Maintenance 2 7 2 Sleep amp Sniff Master lt CR gt activate AT mode ATRE restore defaults ATBD 3 9600 baud ATNB 0 no parity ATPL 4 I watt ATCD 0 GPO2 RxDat LED ATCS 1 assert RTS while receiving data ATSM 2 serial port sleep ATDT DCAB set the networking address ATRO 10 packetization timeout 16 x 1 9600 x 10
18. ietary 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 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
19. ion reception which can be determined by turning the equipment off and on the user is encouraged to try to correct the interference by one or more of the following measures e Reorient or relocate the receiving antenna Increase the separation between the equipment and receiver e Connect the equipment into an outlet on a circuit different from that to which the receiver is connected e Consult the dealer or an experienced radio TV technician for help 1 12 Agency Certifications The 9Xtend RF module complies with Part 15 of the FCC rules and regulations Compliance with the labeling requirements FCC notices and antenna usage guidelines is required by the system integrator The 9XTend module may only be used with antennas that have been tested an approved for use with this module WATERL G H 4271 Introduction 1 5 1 6 Introduction War ER L G H 427 1 SERIES Chapter 2 Installation 2 1 General Installation Recommendations The enclosure and connectors are not weather tight The H 4271 must be installed in a protected location or a weather tight enclosure The housing has a 2 terminal connector for making power connections and a 9 terminal DB 9 connector for the RS 232 port Caution Remove all power from the unit before making any connections 2 2 Power Connection Connect the 12V and GND terminals to a 12V power source Even though the H 4271 normally operates in a low power mode the transmitter reguires 500mA for short
20. m from all persons The power output is emitted at the antenna terminal and can be adjusted from 1 milliwatt to 1 Watt This is an RF module approved for limited modular use operating as a mobile transmitting device with respect to Section 2 1091 and is limited to integrator installation for mobile and fixed applications only it is not approved for portable applications Professional installation adjustment is required for setting module power and antenna gain to meet EIRP compliance for high gain antenna s FCC regulations stipulate a maximum 36 dBm EIRP power limitation Users implementing antenna gain greater than 6 0 dB must compensate for the added gain with cable loss When operating at 1 Watt power output the sum in dB of cable loss and antenna gain shall not exceed 6 0 dB The H 4271 must be used with a 50 ohm 900 MHz antenna The antenna connector is a RPSMA Reverse polarity SMA connector which is required to meet FCC regulations A simple vertical whip antenna will work up to 2 or 3 miles Longer distances require a directional antenna with gain A 6dB YAGI will work fine do not use a 12dB model Please refer to the Antennal Options section of the Digi 9XStream product manual for approved antennas for use with this module At 900 MHz RG58 type coaxial antenna feed lines have excessive loss 1 8dB 10 feet Consider using newer low loss RF cable such as Times Microwave LMR 400 or similar 0 8dB 10 feet The LMR 400 requires sp
21. mended setup configures the slaves with cyclic sleep 4 0 seconds and the Master wake up initializer 10 seconds With this setup the slaves will have sufficient time for two attempts to detect the beacon The protocol for Sleep amp Sniff is implemented by the 9XTend module and requires no intervention by the data logger other than the data logger must be patient The first response from the remote site will require 10 seconds or more An inactivity timer setting can be used to keep both the master and slaves awake for subsequent transmissions without the overhead of sending a beacon for every transmission Sleep amp Sniff is workable with multiple slave stations However the communication protocol must include an in band addressing scheme such as SDI 12 where only one slave will attempt to respond to a specific message With Sleep amp Sniff operation a fault condition can occur is where the slave fails to detect the beacon If subsequent retry messages are sent they will also fail because the slave is asleep The data logger should issue retries by either waiting for the time before sleep inactivity timer to expire before sending a retry or by forcing the retried message to be sent with a beacon This can be done by using the ATFH force wake up initializer command See Chapter 2 for a driver which implements retries WATERL G H 4271 Introduction 1 3 1 9 Repeater Mesh The 9XTend module supports communication topologies which e
22. mploy repeaters When configured as a repeater a node re sends RF data unless the transmission is addressed to it or if the transmission has already been detected A repeater end node handles repeated messages but will not repeat the message over the air Repeater topologies reguire careful design and setup of the system Repeaters will NOT work with Sleep amp Sniff in that all nodes must be continually powered The recommenced setting is ATMD 5 repeater This setup allows all of the nodes in the system be configured identically 1 10 SDI 12 Gateway Applications often arise where a SDI 12 sensor must be physically located hundreds or thousands of feet from the data logger Transparent wireless SDI 12 bridges are available for these applications Unfortunately transparent bridges can miss or drop measurements because of corrupted radio packet transmissions Wireless bridges are problematic because the SDI 12 protocol provides insufficient time to make retries or other recovery When coupled with a H4271 data radio a H 4191 module can be used to construct a non transparent wireless SDI 12 link With this architecture the H 4191 is permanently connected to one or more sensors at the remote site A pair of RS 232 data radios such as the H 4271 are installed between the data logger and the remote H 4191 The data logger must be setup to initiate and collect SDI 12 commands responses from a RS 232 port instead of its normal SDI 12 port SDI
23. on condensing Mechanical Enclosure Anodized Aluminum Size 2 75 x 1 125 x 3 60 in Connectors Antenna RPSMA reverse SMA Data DB9S Power Phoenix 1803277 header Phoenix 1803578 plug 2 position 3 81mm The RF module has the following FCC approval FCC ID OUR 9XTEND IC 4214A 9XTEND Warranty The WATERLOG H 4271 is warranted against defects in materials and workmanship for one year from date of shipment Specifications A 1 2 2 Installation And Maintenance War ER LOG H 427 1 SERTES
24. w system cost e 1 0mW to 1 0Watt power output e 9 18VDC supply voltage Up to 14 mile operation with dipole antenna Supports point to point point to multipoint and repeater operating modes Built in power management including sleep amp sniff modes No configuration necessary for standard point to point communication Free setup configuration and test software 1 1 Description Internally the H 4271 modem employs an industrial 9XTend RF module manufactured by Digi International Inc In addition the modem includes a high efficiency DC DC converter RS 232 transceiver and a power down circuit Complete specifications and a user manual for the 9XTend OEM module are available at www digi com 1 2 Reliability When properly configured and installed the H 4271 telemetry data link will have good performance However as with any radio apparatus interference noise and other factors can corrupt communications Retries and other schemes can help recover from corrupted data or lost messages If your application requires 100 accuracy or you cannot tolerate missing data scans do not use a radio link 1 3 LED Indicators The H 4271 has two LED indicators marked RxDat and TxDat The green RxDat LED flashes whenever a data packet is received The yellow TxDat LED flashes whenever a data packet is transmitted WATERL G H 4271 Introduction 1 1 ERTIES 1 4 Configuration and Programming The H 4271 can be ordered from the factory
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