AvaLAN Wireless AW900R4 User Manual

AvaLAN
W I R E L E S S
AW900R4-EVAL
USER’S MANUAL
900 MHz Wireless RS-485 Module
Evaluation Kit
Industrial-grade, long-range wireless systems
AW900R4-EVAL
Thank you for your purchase of the AW900R4-EVAL Wireless RS-485 Module Evaluation Kit.
If you have any questions when conguring your AvaLAN system, the best place to get answers is to visit www.avalanwireless.com. You will also nd the latest updates there.
If more assistance is needed, send email to support@avalanwireless.com.
To speak to a live technician, please call technical support at the number below during normal business hours.
Limited Warranty
This product is warranted to the original purchaser for normal use for a period of 360 days from the date of purchase. If a defect covered under this warranty occurs, AvaLAN will repair or replace the defective part, at its option, at no cost. This warranty does not cover defects resulting from misuse or modication of the product.
© 2010 by AvaLAN Wireless Systems Inc. All rights reserved.
Revision 06.28.2010
125A Castle Drive
Madison, AL 35758
Sales: (866) 533-6216
Technical Support: (650) 384-0000
Customer Service: (650) 641-3011
Fax: (650) 249-3591
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User’s Manual AW900R4-EVAL
Operational summary
RS-485 is a point-to-multipoint serial data bus that requires just three wires: two differential data lines and a common. Because there is no handshake involved, all devices on the bus must be congured for the same data protocol and timing or communication will not occur. Also, it is possible to lose data if a receiving device cannot keep up with a sending device. The AW900R4 supports data rates from 9600 Baud to 115,200 Baud and has a 4 KB data buffer. A set of AW900R4 modules behave just like an RS-485 bus but without the length constraint and without a physical wire. They can be used to wirelessly interconnect individual RS-485 devices and can also link multiple separate busses.
Conguring a wireless link with the AW900R4 requires the establishment of six elements:
• One radio must be congured as the Access Point (AP) and all others must be congured as Subscriber Units (SU). Up to 16 SUs can be linked to one AP.
• All radios must share a common Network Name, a 32-bit identier.
• All radios must share a common 128-bit encryption key.
• The AP and SUs must agree on which radio frequency channel they are using. This can be manually set or allowed to change automatically.
• The serial port settings: Baud rate, number of data and stop bits and sense of Parity bit, must match between each radio and the RS-485 bus wired to it, although the radio link may have different settings at each end.
• The AP and SUs must share a common set of tuning parameters: Next Byte Delay, Minimum Packet Size and Maximum Packet Size.
AW900R4 modules are congured through a built-in USB port with a utility program from AvaLAN. The LED display on the module PC board is also a very useful indicator of the condition of the wireless connection.
The access point (AP) automatically scans for the best of the 12 available radio fre­quency channels, encrypts RS-485 data received, and broadcasts it wirelessly to all linked subscriber units (SUs). The AP is constantly monitoring the radio link and can automatically change the channel if performance is degraded due to interference. If two AP units are very close to one another, they may interfere if operating on adjacent frequency channels. Place them at least 10 feet apart or manually select non-adjacent channels for their operation. Also, each SU should be placed at least 10 feet from the AP to avoid overloading the radio’s receiver.
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AW900R4-EVAL
Electrical Connections
The AW900R4-EVAL 900 MHz Wireless RS-485 Module Evaluation Kit contains two each of the following items:
• AW900R4 Wireless Ethernet Modules
• AW2-900 Omnidirectional Antennas
• AW-P8 Antenna to Radio Connectors
• 20” USB to Mini-USB Adapter Cables
• 120VAC to 6 VDC Wall Hanger Power Supplies
Additional quantities of any of these components may be purchased from AvaLAN Wireless or our distributors.
To power up a radio module, make connections to it as shown in this diagram:
PC with
Windows XP
or later
Status LEDs
USB
900 MHz Antenna
Plain black wire
White-striped wire
Reset Switch
(cycles power)
Inverting
RS-485
Device(s)
line “A”
Non-Inverting
line “B”
Common
Note:
The USB connection is not needed after the link is congured and operating normally. If the USB cable is connected, the module can draw its power from it. (A high-power USB port is required.)
Provide some physical separation between two radio module antennas — at least ten feet. If their antennas are in close proximity, the module radio receivers will be overloaded, causing degradation in the bit error rate and slower link performance.
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User’s Manual AW900R4-EVAL
Physical Dimensions
66 mm
23 mm
58 mm
18 mm
55 mm
63 mm
15 mm
25 mm
33 mm
18 mm
900 MHz Channels
Channel Center Frequency
0 Auto Mode 1 903.12500 MHz 2 905.20833 MHz 3 907.29167 MHz 4 909.37500 MHz 5 911.45833 MHz 6 913.54167 MHz 7 915.62500 MHz 8 917.70833 MHz
9 919.79167 MHz 10 921.87500 MHz 11 923.95833 MHz 12 926.04167 MHz
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AW900R4-EVAL
Conguration
Setting or changing the conguration (Baud rate, etc.) of the AW900R4 module is done via the USB interface on the board. Follow these steps:
1. The PC that you will connect via USB to the module must have a USB 2.0 or later port available and be running MS Windows XP or later. In addition, three critical pieces of software must be installed; a driver, a utility and a dll.
2. Your PC requires a virtual COM port driver to allow communication with the USB interface chip in the module. This driver may be downloaded from the chip manu­facturer’s website, http://www.ftdichip.com. On their site menu, select “Drivers” and “VCP” (Virtual COM Port). Next, choose the driver corresponding to your PC’s operating system and our chip, which is an FT232R. At this manual’s writing, the correct choice was Driver Version 2.06.02, dated 31 March 2010. Download the zip le from their site. You would also be advised to download the installation guide for your operating system, available from the link at the top of the driver selection page. Extract the driver zip le to a folder of your choice, connect the module to your PC using the supplied USB cable and follow the instructions in the installation guide. Once you are successful, you should be able to navigate to your Windows Device Manager and see something like this in the “Ports” section:
The device labeled “USB Serial Port (COM6) is the connection to the AW900R4 mod­ule. Windows chooses which COM port number to assign, so yours is unlikely to be COM6. In fact, every time you plug and unplug the USB or restart your computer, the assigned COM port number will probably be different. So your rst step when up and running should be to open Device Manager to identify the correct port number.
3. Next, you will need a conguration utility and its associated dll le from AvaLAN. Go to our website, http://www.avalanwireless.com. Navigate to “Support” then “Downloads.” Choose the “AvaLAN Evk Utility Lite” le and download the zip le. This zip archive contains two les, EvkUtilityLite.exe and ZedGraph.dll. Extract both of these to the same folder of your choice. The utility does not use the Windows registry and can be placed anywhere, but the dll must be in the same folder. If Evk Utility Lite refuses to run, check rst to be sure the dll le is there.
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User’s Manual AW900R4-EVAL
4. Run EvkUtilityLite.exe and you should see a window like this:
5. Use the dropdown menu labeled “Boot Cong Serial Port” to select the virtual COM port connected to your AW900R4 module. Note that the list is populated only when EvkUtilityLite rst starts. If you change your cable connection or plug in an­other module, restart the utility to see the changes. Next click the “Get” button to fetch the current conguration from the module.
6. If you are satised with the module’s conguration and status, stop here. If changes are needed, here is an explanation of the parameters that may be set on the Boot Conguration page:
Radio Conguration Meaning
AccessPoint/Subscriber Unit
Number of Subscriber Units/Subscriber ID
Channel 00-12 The RF channel for the module. The frequencies corresponding to each chan-
Network Name A 32-bit value (8 Hex digits, 0 to 9 and A to F) that must be the same for
AES Private Key A 128-bit value (32 Hex digits) that must be the same for the radio modules
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Buttons to select whether this module is the master or the client of the group. Each RS-485 wireless link must have one Access Point master and up to 16 Subscriber Unit clients.
A two digit number, leading zero required. For the Access Point, this should be the number of Subscriber Units to be connected. Subscriber Units must be numbered in sequence: “01”, “02”, etc.
nel are shown in the table on page 5. Choose “00” for automatic channel selection or set “01” to “12” for a xed choice.
the radio modules in the group. If you have multiple wireless RS-485 groups operating in the same vicinity, give each a unique value.
in the group. This key is used to encrypt the transmitted data and decrypt the received data.
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AW900R4-EVAL
Serial Port Settings These settings must match those of the RS-485 bus connected to the module.
Baud Rate Drop down menu providing six choices from 9600 Baud to 115,200 Baud (se-
Data Bits Selectable 7 or 8 data bits (8 is the most common choice)
Parity Selectable among “none”, “even”, “odd”, “mark” or “space” (“none” is the
Stop Bits Select 1 or 2 stop bits (2 is the most common choice)
Tuning Parameters These affect the behavior of the RF packet transmissions relative to the
Next Byte Delay The amount of time the bus must be idle after the Minimum Packet Size has
Minimum Packet Size Expected packet size bytes. Values of 01 to 99 may be chosen, with a default
Maximum Packet Size Maximum number of bytes per transmission. Values from one more than
rial data rate).
most common choice)
incoming serial data. We suggest leaving these at the default values unless the nature of the serial data or the requirements of the protocol being used demand otherwise.
expired before the radio sends everything in it’s serial buffer. Values of 00 to 10 may be chosen, with a default of 00. Each unit of time is the reciprocal of the Baud Rate (e.g. 104 µs at 9600 Baud).
of 01. Packets smaller than this will wait to see if additional packets arrive during this time window. If additional packets arrive, they will be combined into a single transmission.
the Minimum Packet Size to 768 may be chosen with a default of 024 bytes. Packets larger than this size will be sent over the RF as fragments and reas­sembled at the receiver radio.
7. Here is additional information about the tuning parameters. The data protocol you are using may require certain groupings of the bytes or particular timing of the information:
• If you want minimum latency so that data is received as soon as possible af-
ter it is sent, select a Next Byte Delay of 00 and a Minimum Packet Size of 01.
• If you are sending large blocks of data, a Minimum Packet Size of 01 can
cause the AW900R4’s buffer to overow and bytes will be lost. The value can be increased to a maximum that depends on the Baud Rate, corresponding to about 5.3 milliseconds:
Baud Rate largest Minimum Packet Size
9600 5
19200 10
38400 20
57600 30
76800 40
115200 60
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User’s Manual AW900R4-EVAL
• Dumping a large volume of data at a xed high Baud rate runs the risk of data corruption if anything (tuning, noise retries, channel switching, etc.) causes the 4 KB buffer in the sending radio to be overwritten.
8. The AW900R4’s chosen conguration can be saved to a local data le for future use by clicking the “Save” button. You might want to do this when conguring both ends of a link since many of the parameters will be the same. The conguration can then be retrieved using the “Load” button. In each case, a File Explorer popup al­lows you to save and retrieve the cong le to a location of your choice. The default lename is EVK.conf.
9. When you are ready to upload the conguration to the AW900R4 module, click the “Send” button. This uploads the conguration and causes the module to reboot. You can reboot without upload by clicking “Reboot Target.” Keep straight which COM port belongs to which USB interface. It is common to connect the two modules of a link at the same time to two different USB ports and if you get confused about which port is which, the wrong conguration can be overwritten.
10. After all modules in the group are congured and rebooted, they should success­fully nd each other and link. The successful accomplishment of this linkage can be determined either by the Stats & Spectrum tab in EvkUtilityLite or by seeing the correct pattern of LEDs on the modules.
11. Click the Stats & Spectrum tab at the top of the EvkUtilityLite window. Make sure that you select the right COM port with the dropdown menu at the top. (It will not change automatically to match the port selected on the Boot Conguration tab.) This page will appear:
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AW900R4-EVAL
12. A snapshot of the module’s status can be retrieved by clicking the “Get Stats” button. Here is an explanation of the values returned:
Name Meaning
RSSI Received Signal Strength Indication in dBm. This is useful when aligning
Radio Block Error Rate Percentage of radio data blocks that are incorrectly received.
Radio Failed Packets Count of failed data packets since the last reboot. This may remain zero
Radio Passed Packets Count of successful data packets since the last reboot.
Radio Total Packets Total packets transmitted since last reboot.
Radio Average TX Size Average bytes transmitted per packet, a function of the serial data source
Radio Average RX Size Average bytes received per packet, a function of the serial data source and
Current RF Channel The RF channel currently in use. If a xed channel is congured, this
Connected Subscribers/ Subscriber Key
RF Connected True if the radio is linked and able to exchange data. False otherwise.
Radio Active True if the radio has a valid conguration and is linked or searching for a
Radio Version 900 MHz Full Band for this product.
Radio Firmware Release The version of the rmware running in this module. Check www.avalan-
antennas or evaluating path attenuation.
because of retries even when the Radio Block Error Rate climbs because of a poor connection.
and the selected tuning parameters.
the selected tuning parameters.
number should match. If automatic selection, this number may change from time to time as the radios look for the channel with the lowest block error rate.
For the AP, the number of SUs linked; for each SU, the ID number assigned to it.
link. False otherwise.
wireless.com from time to time to see if a later version is available.
13. The Spectrum Scan may be used to identify interference issues. When “Get Spectrum Scan” is clicked, the module’s transmitter is disabled, interrupting the serial data ow. The receiver is tuned across the 900 MHz band and the RSSI is plot­ted for each frequency. You can select the frequency step size and the number of samples to be taken and averaged at each frequency. The smaller the step size and the larger the number of samples averaged, the longer the scan will take. If you perform a scan from a Subscriber Unit, you may see large transient spikes caused by the Access Point scanning the channels because the Subscriber Unit has gone off line. Scanning from the Access Point will show a better picture of external interfer­ence sources. After a spectrum scan, the radio will resume normal operation.
14. The LEDs on the AW900R4 PC board can be very useful in determining whether the link is operating normally or if not, where the trouble might be. The next page shows where these LEDs are located and the meaning of each.
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User’s Manual AW900R4-EVAL
Reset Switch:
Press momentarily to cycle power and reboot the module.
DIP Switches
(only used during factory testing)
LEDs
LED Function Color
SER RX Blinks when module is receiving RS-485 data Green SER TX Blinks when module is transmitting RS-485 data Green RF RX Blinks when module is receiving RF data Green RF TX Blinks when module is transmitting RF data Green CH1 By adding the numbers that are lit, you can determine the cur­CH2 CH4 CH8 CH16 CH32 Shows link quality (more
lit the better) or indicates “key exchange mode” if blinking sequentially
PWR Lit when the module has DC power Red USB RX Located between the USB and power connectors, these LEDs USB TX Amber
rent radio channel. Valid channels are 1 to 12, CH16 and CH32 are not used. For the frequency of each channel, see the table on page 5.
Excellent link quality: no retransmissions Green Very good link quality: few retransmissions Green Good link quality: occasional retransmissions Amber Fair link quality: some retransmissions Amber Poor link quality: frequent retransmissions Red No link quality: no link available Red
indicate activity through the USB port.
Green
Amber
If LEDs CH1 to CH8 are cycling in a binary count and only the bottom link quality LED is lit, the radio is active and searching for another module to link to. When link is accomplished, the Channel LEDs will stop, showing the RF channel selected and the link quality LEDs will show the signal strength.
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PAGE 11
AW900R4-EVAL
Example Test Method
If you already have a suitable RS-485 data source and an equally suitable destina­tion, you will probably want to evaluate the AW900R4 capability with those. If you do not, you might consider using USB to Serial converters and hyperterm or some other terminal emulator program.
Here is a block diagram of a possible evaluation test setup:
USB Conguration & Status
PC
PC
USB to RS-485
USB Data
USB Data
Converter
USB Conguration & Status
USB to RS-485
Converter
RS-485 Data
RS-485 Data
AW900R4
RF Data
AW900R4
Notes about this test setup:
1. One PC could be used rather than two, but you then need 4 available high power USB 2.0 ports and it is difcult to physically separate the radio antennas sufciently.
2. The PCs need to be running Windows XP or later.
3. There are a number of inexpensive USB to RS-485 converters on the market. We used a pair of GC-ATC-820 USB-High Speed Serial Converters available from Grid Connect (www.gridconnect.com). These converters have a driver CD in­cluded and have a 9-pin DB9 connector plus a screw terminal breakout adapter with the signals labeled.
4. You will need to install Virtual COM Port drivers for both the USB to RS-485 con­verters and for the conguration and status ports on the AW900R4s. In device manager on your PC, you will see COM ports for both the serial converter and the AW900R4. Connect these one at a time and note the assigned port numbers to keep them straight.
5. You will need to install EvkUtilityLite.exe and zedgraph.dll on the PC. If you attempt to select the serial converter’s COM port with the utility, you will get
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User’s Manual AW900R4-EVAL
a “port closed” error, but no harm will be done.
6. You will need a serial data source program installed on your PC. If you are run­ning Windows XP, hyperterm is already there and makes a good data source. Unfortunately, Microsoft has discontinued inclusion of hyperterm and you will need another alternative for later versions of Windows. There are many avail­able for free or at low cost and they may be found by Internet search. The one we used in our setup was Tera Term, a free terminal emulator whose latest ver­sion can be downloaded from sourceforge: ttssh2.sourceforge.jp. The terminal emulator program should be congured to connect to the Virtual COM port of the Serial Converter and its serial port properties like Baud rate, data bits, etc. should match the conguration settings in the AW900R4. It is also useful to set local echo and CR-LF end-of-line for transmit and receive.
7. When everything is connected properly and all the software pieces are in place, you should be able to type characters into the terminal emulator on one PC and see them appear in the terminal emulator window on the other PC. Tera Term also supports text le transfers if you want to send more data than what you are willing to type or wish to explore the effect of the radio’s tuning parameters on the data stream.
8. With the AW900R4 modules, you can interconnect multiple RS-485 busses. An interesting conguration to consider uses the Access Point as a coordinator/ repeater with no serial devices connected to it at all:
Access Point
Coordinator/Repeater
RF Data
at 1000 Kbps
AW900R4
Up to 16
AW900R4
RS-485 Busses
RS-485
Device 1
RS-485
Device 2
RS-485
Device 3
at 115.2 Kbps
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AW900R4
RS-485
Device 4
PAGE 13
Subscriber Units
AW900R4
RS-485
Device N
(up to 32)
AW900R4-EVAL
Notes
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PAGE 14
User’s Manual AW900R4-EVAL
Technical specications
Characteristic Specication/Description
Serial Baud Rate 9600, 19200, 38400, 57600, 76800, 115200
RS-485 Signal Characteristics See data sheet for Maxim 3079E chip (www.maxim-ic.com)
RF transmission rate 1.536 Mbps
RF Output Power +21 dBm (4 Watts EIRP with 15 dBi antenna)
Receiver Sensitivity -97 dBm at 10-4 Bit Error Rate
Radio Link Budget 148 dB with 15 dBi antennas
Range Up to 40 miles line-of-sight with 15 dBi antennas
RF channels/bandwidth 12 non-overlapping with 2.0833 MHz spacing and 1.75 MHz
Channel selection Automatic or manual via USB interface
Adjacent band rejection SAW receiver lter attenuates cellular and pager interfer-
Error correction Sub-block error detection and retransmission
Encryption 128-bit AES, meets FIPS 197 Standard
Evk Utility Management Tools Serial port conguration, encryption keys, tuning param-
Status LEDs power, RF activity, serial data activity, channel, link qual-
Connectors RF: RPSMA Female, RS-485, power: Phoenix screw termi-
Power consumption Transmit: 0.54 Watts, Receive: 0.45 Watts
Voltage 5-45 VDC
Power regulation Switching regulator
Transmit current draw 175 ma at 9 VDC
Operating Temperature Range -40 ºC to +80 ºC
Size 99 by 66 by 23 mm, 46 grams, connectors included
bandwidth
ence
eters, QoS statistics, spectrum analyzer
ity
nals
140 ma at 12 VDC 35 ma at 48 VDC
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PAGE 15
AW900R4-EVAL
FCC Certication
The AW900R4 OEM RF Module complies with Part 15 of the FCC rules and regulations. Compliance with labeling requirements, FCC notices and antenna regulations is required. IMPORTANT: The AW900R4 OEM RF Modules have been certied by the FCC for use with other products without any further certication (as per FCC section 2.1091). Changes or modications not expressly approved by AvaLAN could void the user’s authority to operate the equipment. IMPORTANT: OEMs must test their nal product to comply with unintentional radiators (FCC section 15.107 and 15.109) before declaring compliance of their nal product to Part 15 of the FCC Rules. IMPORTANT: The AW900R4 OEM RF Modules have been certied for xed base station and mobile applications. If modules will be used for portable applications, the device must undergo SAR testing.
Labeling Requirements
In order to inherit AvaLAN’s FCC Certication, compliance requires that the following be stated on the device:
Contains FCC ID: R4N-AW900MR The enclosed device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) this device may not cause harmful interference and (2) this device must accept any interference received, including interference that may cause undesired operation.
The Original Equipment Manufacturer (OEM) must ensure that FCC labeling requirements are met. This includes a clearly visible label on the outside of the nal product enclosure that displays the contents shown in the box above.
User’s Manual Requirements
In order to inherit AvaLAN’s FCC Certication, compliance requires that the following be stated in the user’s manual:
Compliance Statement ( Part 15.19 )
This device complies with Part 15 of the FCC Rules. Operation is subject to the following two conditions:
1. This device may not cause harmful interference, and
2. This device must accept any interference received, including interference that may cause undesired operation.
Warning ( Part 15.21 )
Changes or modications not expressly approved by the party responsible for compliance could void the user’s authority to operate the equipment. RF Exposure ( OET Bulletin 65 ) To comply with FCC RF exposure requirements for mobile transmitting devices, this transmitter should only be used or installed at locations where there is at least 20cm separation distance between the antenna and all persons.
Information to the User - Part 15.105 (b)
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 television 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:
--Reorient or relocate the receiving antenna.
--Increase the separation between the equipment and receiver.
--Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
--Consult the dealer or an experienced radio/TV technician for help.
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PAGE 16
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