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Aprisa SRi
User Manual
297 pgs5.81 Mb0

4RF Aprisa SRi User Manual

0 (0)
Standard Radio
July 2016
Version 1.0.0b
| 1
Copyright
Copyright © 2016 4RF Limited. All rights reserved.
This document is protected by copyright belonging to 4RF Limited and may not be reproduced or republished in whole or part in any form without the prior written permission of 4RF Limited.
Trademarks
Aprisa and the 4RF logo are trademarks of 4RF Limited.
Windows is a registered trademark of Microsoft Corporation in the United States and other countries. Java and all Java-related trademarks are trademarks or registered trademarks of Sun Microsystems, Inc. in the United States and other countries. All other marks are the property of their respective owners.
Disclaimer
Although every precaution has been taken preparing this information, 4RF Limited assumes no liability for errors and omissions, or any damages resulting from use of this information. This document or the equipment may change, without notice, in the interests of improving the product.
RoHS and WEEE Compliance
The Aprisa SRi is fully compliant with the European Commission’s RoHS (Restriction of Certain Hazardous Substances in Electrical and Electronic Equipment) and WEEE (Waste Electrical and Electronic Equipment) environmental directives.
Restriction of hazardous substances (RoHS)
The RoHS Directive prohibits the sale in the European Union of electronic equipment containing these hazardous substances: lead, cadmium, mercury, hexavalent chromium, polybrominated biphenyls (PBBs), and polybrominated diphenyl ethers (PBDEs).
4RF has worked with its component suppliers to ensure compliance with the RoHS Directive which came into effect on the 1st July 2006.
End-of-life recycling programme (WEEE)
The WEEE Directive concerns the recovery, reuse, and recycling of electronic and electrical equipment. Under the Directive, used equipment must be marked, collected separately, and disposed of properly.
4RF has instigated a programme to manage the reuse, recycling, and recovery of waste in an environmentally safe manner using processes that comply with the WEEE Directive (EU Waste Electrical and Electronic Equipment 2002/96/EC).
4RF invites questions from customers and partners on its environmental programmes and compliance with the European Commission’s Directives (sales@4RF.com).
2 |
Compliance General
The Aprisa SRi radio predominantly operates within frequency bands that are covered under a class license or general user license which is a license is issued to ‘every person’.
Changes or modifications not approved by the party responsible for compliance could void the user’s
authority to operate the equipment.
Equipment authorizations sought by 4RF are based on the Aprisa SRi radio equipment being installed at a fixed restricted access location and operated in point-to-multipoint or point-to-point mode within the environmental profile defined by EN 300 019, Class 3.4. Operation outside these criteria may invalidate the authorizations and / or license conditions.
The term ‘Radio’ with reference to the Aprisa SRi User Manual, is a generic term for one end station of a point-to-multipoint Aprisa SRi network and does not confer any rights to connect to any public network or to operate the equipment within any territory.
| 3
Radio
47CFR part 15.247
EMC
47CFR part 15 Radio Frequency Devices
Environmental
EN 300 019, Class 3.4 Ingress Protection IP51
Safety
EN 60950-1:2006 Class 1 division 2 for hazardous locations
Frequency Band *
Channel size
Power input
Authorization
FCC ID
902-928 MHz
50 kHz
13.8 VDC
Part 15.247
Pending
Compliance Federal Communications Commission
The Aprisa SRi radio is designed to comply with the USA Federal Communications Commission (FCC) specifications as follows:
NOTE: This equipment has been tested and found to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference when the equipment is operated in a commercial environment. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instruction manual, may cause harmful interference to radio communications. Operation of this equipment in a residential area is likely to cause harmful interference in which case the user will be required to correct the interference at his own expense.
* The Frequency Band is not an indication of the exact frequencies approved by FCC.
4 |
Radio
RSS-247
EMC
This Class A digital apparatus complies with Canadian standard ICES-003.
Cet appareil numérique de la classe A est conforme à la norme NMB-003 du Canada.
Environmental
EN 300 019, Class 3.4 Ingress Protection IP51
Safety
EN 60950-1:2006 Class 1 division 2 for hazardous locations
Frequency Band *
Channel size
Power input
Authorization
IC
902-928 MHz
50 kHz
13.8 VDC
RSS-247
Pending
Compliance Industry Canada
The Aprisa SRi radio is designed to comply with Industry Canada (IC) specifications as follows:
* The Frequency Band is not an indication of the exact frequencies approved by IC.
This device complies with Part 15 of the FCC Rules and Industry Canada’s licence exempt RSSs. Operation
is subject to the following two conditions: (1) This device may not cause interference; and (2) This device must accept any interference, including interference that may cause undesired operation of the device.
Ce dispositif est conforme à la partie 15 des règles de la Federal Communications Commission (FCC) des États Unis et d'Industrie Canada (IC) exempts de licence RSS norme(s). Son fonctionnement est assujetti aux deux conditions suivantes: (1) Ce dispositive nedoit pas provoquer de brouillage préjudiciable, et (2) il doit accepter tout brouillagereçu, y compris le brouillage pouvant entraîner unmauvais fonctionnement.
| 5
Radio
Radio Communications (Short Range Devices) Standard 2004
EMC
AS/NZS 4268
Environmental
EN 300 019, Class 3.4 Ingress Protection IP51
Safety
EN 60950-1:2006 Class 1 division 2 for hazardous locations
Frequency Band *
Channel size
Power input
Authorization
ACMA
915-928 MHz
50 kHz
13.8 VDC
Pending
Radio / EMC
AS/NZS 4268
Environmental
EN 300 019, Class 3.4 Ingress Protection IP51
Safety
EN 60950-1:2006 Class 1 division 2 for hazardous locations
Frequency Band *
Channel size
Power input
Authorization
RSM
915-928 MHz
50 kHz
13.8 VDC
Licence 252286
Pending
Compliance ACMA
The Aprisa SRi radio is designed to comply with Australia ACMA specifications as follows:
Compliance RSM
The Aprisa SRi radio is designed to comply with New Zealand RSM specifications as follows:
6 |
Compliance Hazardous Locations Notice
This product is suitable for use in Class 1, Division 2, Groups A - D hazardous locations or non-hazardous locations.
The following text is printed on the Aprisa SRi fascia:
WARNING: EXPLOSION HAZARD - Do not connect or disconnect while circuits are live unless area is known to be non-hazardous.
The following text is printed on the Aprisa SRi where the end user is in Canada:
AVERTISSEMENT: RISQUE D'EXPLOSION - Ne pas brancher ou débrancher tant que le circuit est sous tension, à moins qu'il ne s'agisse d'un emplacement non dangereux.
The USB service ports are not to be used unless the area is known to be non-hazardous.
| 7
WARNING:
The installer and / or user of Aprisa SRi radios shall ensure that a separation distance as given in the following table is maintained between the main axis of the terminal’s antenna and the body of the user or nearby persons.
Minimum separation distances given are based on the maximum values of the following methodologies:
1. Maximum Permissible Exposure non-occupational limit (B or general public) of 47 CFR 1.1310 and the methodology of FCC’s OST/OET Bulletin number 65.
2. Reference levels as given in Annex III, European Directive on the limitation of exposure of the general public to electromagnetic fields (0 Hz to 300 GHz) (1999/519/EC). These distances will ensure indirect compliance with the requirements of EN 50385:2002.
Frequency (MHz)
Maximum Power
(dBm)
Note 1
Maximum Antenna
Gain (dBi)
Minimum Separation
Distance
(m)
915
+ 26
10 dBi
0.3
RF Exposure Warning
Note 1: The Peak Envelope Power (PEP) at maximum set power level is 1.0 W ,+30 dBm.
Contents | 9
Contents
1. Getting Started ........................................................................ 13
2. Introduction ............................................................................ 15
About This Manual ............................................................................... 15
What It Covers ............................................................................ 15
Who Should Read It ...................................................................... 15
Contact Us ................................................................................. 15
What’s in the Box ............................................................................... 15
Aprisa SRi Accessory Kit ................................................................. 16
Aprisa SRi CD Contents .................................................................. 16
Software ............................................................................ 16
Documentation .................................................................... 16
3. About the Radio ....................................................................... 17
The 4RF Aprisa SRi Radio ....................................................................... 17
Product Overview ............................................................................... 18
Network Coverage and Capacity ....................................................... 18
Automatic Registration .................................................................. 18
Remote Messaging ........................................................................ 18
Product Features ................................................................................ 19
Functions .................................................................................. 19
Security .................................................................................... 20
Performance .............................................................................. 21
Usability ................................................................................... 21
System Gain vs FEC Coding ............................................................. 22
Architecture ...................................................................................... 23
Product Operation ........................................................................ 23
Physical Layer ............................................................................. 23
Data Link Layer / MAC layer ............................................................ 24
Channel Access .................................................................... 24
Hop by Hop Transmission ......................................................... 25
Adaptive Coding and Modulation ................................................ 25
Network Layer ............................................................................ 26
Packet Routing ..................................................................... 26
Static IP Router .................................................................... 27
Bridge Mode with VLAN Aware .................................................. 30
VLAN Bridge Mode Description .................................................. 31
Avoiding Narrow Band Radio Traffic Overloading .................................... 33
Interfaces ......................................................................................... 35
Antenna Interface ........................................................................ 35
Ethernet Interface ....................................................................... 35
RS-232 / RS-485 Interface ............................................................... 35
USB Interfaces ............................................................................ 35
Protect Interface ......................................................................... 35
Alarms Interface .......................................................................... 35
Front Panel Connections ....................................................................... 36
LED Display Panel ............................................................................... 37
Single Radio Software Upgrade ......................................................... 38
Network Software Upgrade ............................................................. 38
Test Mode ................................................................................. 39
10 | Contents
Network Management.................................................................... 40
Hardware Alarm Inputs / Outputs ............................................................ 41
Alarm Input to SNMP Trap ............................................................... 41
Alarm Input to Alarm Output ........................................................... 41
Aprisa SR Alarm Input to Aprisa SRi Alarm Output ................................... 41
4. Implementing the Network.......................................................... 42
Network Topologies ............................................................................. 42
Point-To-Point Network .......................................................... 42
Point-to-Multipoint Network ..................................................... 42
Initial Network Deployment ................................................................... 43
Install the Base Station .................................................................. 43
Installing the Remote Stations ......................................................... 43
Network Changes ................................................................................ 44
Adding a Remote Station ................................................................ 44
5. Preparation ............................................................................ 45
Bench Setup ...................................................................................... 45
Compliance Considerations .................................................................... 46
Path Planning .................................................................................... 48
Antenna Selection and Siting ........................................................... 48
Base Station ........................................................................ 48
Remote station .................................................................... 49
Antenna Siting ..................................................................... 50
Coaxial Feeder Cables ................................................................... 51
Linking System Plan ...................................................................... 51
Site Requirements ............................................................................... 52
Power Supply .............................................................................. 52
Equipment Cooling ....................................................................... 52
Earthing and Lightning Protection ..................................................... 53
Feeder Earthing .................................................................... 53
Radio Earthing ..................................................................... 53
6. Installing the Radio ................................................................... 54
Mounting .......................................................................................... 54
Required Tools ............................................................................ 54
DIN Rail Mounting ........................................................................ 55
Rack Shelf Mounting ..................................................................... 56
Wall Mounting ............................................................................. 57
Installing the Antenna and Feeder Cable .................................................... 58
Connecting the Power Supply ................................................................. 59
External Power Supplies ................................................................. 59
Spare Fuses ................................................................................ 60
Additional Spare Fuses ............................................................ 61
Contents | 11
7. Managing the Radio ................................................................... 63
SuperVisor ........................................................................................ 63
PC Requirements for SuperVisor ....................................................... 64
Connecting to SuperVisor ............................................................... 65
Management PC Connection ..................................................... 66
PC Settings for SuperVisor ....................................................... 67
Login to SuperVisor................................................................ 71
Logout of SuperVisor .............................................................. 72
SuperVisor Page Layout ........................................................... 73
SuperVisor Menu ................................................................... 75
SuperVisor Menu Access .......................................................... 76
Standard Radio............................................................................ 78
Terminal ............................................................................ 78
Radio ................................................................................ 89
Serial .............................................................................. 106
Ethernet .......................................................................... 116
IP................................................................................... 126
QoS ................................................................................ 139
Security ........................................................................... 161
Maintenance ..................................................................... 183
Events ............................................................................. 197
Software .......................................................................... 208
Monitoring ........................................................................ 227
Network Status .................................................................. 246
Command Line Interface .............................................................. 253
Connecting to the Management Port ................................................ 253
CLI Commands .......................................................................... 256
Viewing the CLI Terminal Summary ........................................... 257
Changing the Radio IP Address with the CLI ................................. 257
8. In-Service Commissioning .......................................................... 258
Before You Start ............................................................................... 258
What You Will Need .................................................................... 258
Antenna Alignment ............................................................................ 259
Aligning the Antennas ................................................................. 259
9. Product Options ...................................................................... 260
Country Specific Products .................................................................... 260
USB Serial Ports ................................................................................ 261
USB RS-232 / RS-485 Serial Port ...................................................... 261
USB RS-232 / RS-485 operation ....................................................... 261
USB RS-232 Cabling Options ........................................................... 262
USB RS-485 Cabling Options ........................................................... 262
USB Retention Clip .............................................................. 263
10. Maintenance .......................................................................... 265
No User-Serviceable Components ........................................................... 265
Software Upgrade ............................................................................. 266
Network Software Upgrade ........................................................... 266
Single Radio Software Upgrade ....................................................... 268
File Transfer Method ............................................................ 268
USB Boot Upgrade Method ..................................................... 269
Software Downgrade ............................................................ 269
12 | Contents
11. Interface Connections ............................................................... 270
RJ45 Connector Pin Assignments ............................................................ 270
Ethernet Interface Connections ............................................................. 270
RS-232 Serial Interface Connections ........................................................ 271
RS-232 Pinout .................................................................... 271
RS-232 Customer Cable Wiring ................................................ 271
RS-232 RJ45 LED Indicators .................................................... 271
Alarm Interface Connections ................................................................ 272
12. Alarm Types and Sources ........................................................... 273
Alarm Types .................................................................................... 273
Alarm Events ............................................................................ 274
Informational Events ................................................................... 278
13. Specifications ......................................................................... 279
RF Specifications .............................................................................. 279
Frequency Bands ....................................................................... 279
Channel Sizes ........................................................................... 279
Receiver ................................................................................. 280
Transmitter ............................................................................. 282
Spread Spectrum ....................................................................... 282
Modem ................................................................................... 283
Data Payload Security ................................................................. 283
Interface Specifications ...................................................................... 284
Ethernet Interface ..................................................................... 284
RS-232 Asynchronous Interface ....................................................... 285
Hardware Alarms Interface ........................................................... 286
Power Specifications .......................................................................... 287
Power Supply ............................................................................ 287
Power Consumption .................................................................... 287
Power Dissipation ...................................................................... 287
General Specifications ........................................................................ 288
Environmental .......................................................................... 288
Mechanical .............................................................................. 288
Compliance .............................................................................. 289
14. Product End Of Life .................................................................. 290
15. Copyrights ............................................................................. 291
16. Abbreviations ......................................................................... 293
17. Index ................................................................................... 294
End-of-Life Recycling Programme (WEEE) ................................................. 290
The WEEE Symbol Explained .......................................................... 290
WEEE Must Be Collected Separately ................................................. 290
YOUR ROLE in the Recovery of WEEE ................................................ 290
EEE Waste Impacts the Environment and Health .................................. 290
Getting Started | 13
Phase 1:
Pre-installation
1.
Confirm path planning.
Page 48
2.
Ensure that the site preparation is complete:
Power requirements Tower requirements Environmental considerations, for example, temperature control Mounting space
Page 51
Phase 2:
Installing the radios
1.
Mount the radio.
Page 54
2.
Connect earthing to the radio.
Page 53
3.
Confirm that the:
Antenna is mounted and visually aligned Feeder cable is connected to the antenna Feeder connections are tightened to recommended level Tower earthing is complete
4.
Install lightning protection.
Page 53
5.
Connect the coaxial jumper cable between the lightning protection and the radio antenna port.
Page 58
6.
Connect the power to the radio.
Page 59
1. Getting Started
This section is an overview of the steps required to commission an Aprisa SRi radio network in the field:
14 | Getting Started
Phase 3:
Establishing the link
1.
If radio’s IP address is not the default IP address (169.254.50.10 with a subnet mask of 255.255.0.0) and you don’t know the radio’s IP address see ‘Command Line Interface’ on page 253.
Page 253
2.
Connect the Ethernet cable between the radio’s Ethernet port and the PC.
3.
Confirm that the PC IP settings are correct for the Ethernet connection:
IP address Subnet mask Gateway IP address
Page 67
4.
Open a web browser and login to the radio.
Page 71
5.
Set or confirm the RF characteristics:
TX / RX frequency TX output power Zone / channel selection
Page 101
6.
Compare the actual RSSI to the expected RSSI value (from your path planning).
Page 235
7.
Align the antennas.
Page 259
8.
Confirm that the radio is operating correctly; the OK, MODE and AUX LEDs are green.
Introduction | 15
4RF Limited
26 Glover Street, Ngauranga
PO Box 13-506
Wellington 6032
New Zealand
E-mail
support@4rf.com
Web site
www.4rf.com
Telephone
+64 4 499 6000
Facsimile
+64 4 473 4447
Attention
Customer Services
2. Introduction
About This Manual
What It Covers
This user manual describes how to install and configure an Aprisa SRi point-to-multipoint digital radio network.
It specifically documents an Aprisa SRi radio running system software version 1.0.0 .
It is recommended that you read the relevant sections of this manual before installing or operating the radios.
Who Should Read It
This manual has been written for professional field technicians and engineers who have an appropriate level of training and experience.
Contact Us
If you experience any difficulty installing or using Aprisa SRi after reading this manual, please contact Customer Support or your local 4RF representative.
Our area representative contact details are available from our website:
What’s in the Box
Inside the box you will find:
One Aprisa SRi radio fitted with a power connector. One Aprisa SRi Accessory kit containing the following:
Aprisa SRi CD Aprisa SRi Quick Start Guide Management Cable
16 | Introduction
Aprisa SRi Quick Start Guide
Aprisa SRi CD
Management Cable USB Cable USB A to USB micro B, 1m
Aprisa SRi Accessory Kit
The accessory kit contains the following items:
Aprisa SRi CD Contents
The Aprisa SRi CD contains the following:
Software
The latest version of the radio software (see ‘Software Upgrade’ on page 266) USB Serial Driver Web browsers - Mozilla Firefox and Internet Explorer are included for your convenience Adobe™ Acrobat® Reader® which you need to view the PDF files on the Aprisa SRi CD
Documentation
User manual - an electronic (PDF) version for you to view online or print Product collateral - application overviews, product description, quick start guide, case studies,
software release notes and technical papers
About the Radio | 17
3. About the Radio
The 4RF Aprisa SRi Radio
The 4RF Aprisa SRi is a Point-To-Multipoint (PMP) digital radio providing 915 MHz Industrial Licence Free Spread Spectrum communications.
The radios carry a combination of serial data and Ethernet data between the base station and remote stations.
A single Aprisa SRi is configurable as a Point-To-Multipoint base station or remote station.
18 | About the Radio
Product Overview
Network Coverage and Capacity
The Aprisa SRi has a typical link range of up to 50 km, however, geographic features, such as hills, mountains, trees and foliage, or other path obstructions, such as buildings, will limit radio coverage. Additionally, geography may reduce network capacity at the edge of the network where errors may occur and require retransmission. However, the Aprisa SRi uses 0.4 W (+26 dBm) output power and Forward Error Correction (FEC) which greatly improves the sensitivity and system gain performance of the radio resulting in less retries and minimal reduction in capacity.
Ultimately, the overall performance of any specific network will be defined by a range of factors including the RF output power, the modulation used and its related receiver sensitivity, the geographic location, the number of remote stations in the base station coverage area and the traffic profile across the network. Effective network design will distribute the total number of remote stations across the available base stations to ensure optimal geographic coverage and network capacity.
One base station can register and operate with up to 500 remote stations.
The practical limit of remote stations that can operate with one base station is determined by a range of factors including the number of services, the packet sizes, the protocols used, the message types and network timeouts.
Automatic Registration
On start-up, the remote station listens for the base station before attempting registration. It then transmits a registration message to the base station which responds with a registration response. The base station records the details of all the remote stations active in the network.
If a remote station cannot register with the base station after multiple attempts within 10 minutes, it will automatically reboot. If remote is not able to register with base station in 5 attempts, then a ‘Network
Configuration Warning’ alarm event will be raised indicating that a remote is not registered with the base
station.
If a remote station has registered with the base station but then loses communication, it will automatically reboot within 2 minutes.
Remote Messaging
There are two message types in the Aprisa SRi network, broadcast messages and unicast messages. Broadcast messages are transmitted by the base station to the remote stations and unicast messages are transmitted by the remote station to the base station. These messages are commonly referred to as uplink (unicast remote to base) and downlink (broadcast base to remote).
All remotes within the coverage area will receive broadcast messages and pass them on to either the Ethernet or serial interface. The RTU determines if the message is intended for it and will accept it or discard it.
About the Radio | 19
Product Features
Functions
Point-to-Multipoint (PMP) operation Unlicensed frequency bands in the frequency range of 902-928 MHz as permitted by the local
regulator
Channel size of 50 kHz Half duplex RF Point-To-Multipoint operation Military style jam resistant frequency hopping spread spectrum technology operating where other
licence free radios have difficulty in break through
Full band and reduced non-overlapping zone options allow a tailored approach to interference
management for maximum range
Ethernet data interface and RS-232 / RS-485 asynchronous Data encryption and authentication using 128,192 and 256 bit AES and CCM security standards Terminal server operation for transporting RS-232 / RS-485 traffic over IP or Ethernet and
converting IP packets to a local physical serial port
SLIP support for RS-232 IEEE 802.1Q VLAN support with single and double VLAN tagged and add/remove VLAN manipulation
to adapt to the appropriate RTU / PLCs
QoS supports using IEEE 802.1p VLAN priority bits to prioritize and handle the VLAN / traffic types QoS per port (Ethernet, serial, management) L2 / L3 / L4 filtering for security and avoiding narrow band radio network overload L3 Gateway Router mode with standard static IP route for simple routing network integration L3 Router mode with per Ethernet interface IP address and subnet L2 Bridge mode with VLAN aware for standard Industrial LAN integration Ethernet and serial payload compression to increase the narrow band radio capacity SuperVisor web management support for element and sub-network management SNMPv1/2/3 & encryption MIB supports for 4RF SNMP manager or third party SNMP agent network
management
SNMP context addressing for compressed SNMP access to remote stations SNTP for accurate wide radio network time and date RADIUS security for remote user authorization, authentication and accounting Transparent to all common SCADA protocols; e.g. Modbus, IEC 60870-5-101/104, DNP3 or similar Complies with international standards, including FCC, EMC, safety and environmental standards
20 | About the Radio
Security
The Aprisa SRi provides security features to implement the key recommendations for industrial control systems. The security provided builds upon the best in class from multiple standards bodies, including:
IEC/TR 62443 (TC65) ‘Industrial Communications Networks – Network and System Security’ IEC/TS 62351 (TC57) ‘Power System Control and Associated Communications – Data and
Communication Security’
FIPS PUB 197, NIST SP 800-38C, IETF RFC3394, RFC3610 and IEEE P1711/P1689/P1685 FIPS 140-2: Security Requirements for Cryptographic Modules
The security features implemented are:
Data encryption
Counter Mode Encryption (CTR) using Advanced Encryption Standard (AES) 128, 192, 256 bit, based on FIPS PUB 197 AES encryption (using Rijndael version 3.0)
Data authentication
NIST SP 800-38C Cipher Block Chaining Message Authentication Code (CBC-MAC) based on RFC 3610 using Advanced Encryption Standard (AES)
Data payload security
CCM Counter with CBC-MAC integrity (NIST special publication 800-38C)
Secured management interface protects configuration L2 / L3 / L4 Address filtering enables traffic source authorization Proprietary physical layer protocol and modified MAC layer protocol based on standardized IEEE
802.15.4
SNMPv3 with Encryption for NMS secure access Secure USB software upgrade Key Encryption Key (KEK) based on RFC 3394, for secure Over The Air Re-keying (OTAR) of
encryption keys
User privilege allows the accessibility control of the different radio network users and the user
permissions
About the Radio | 21
Performance
Typical deployment of 30 remote stations from one base station with a practical limit of a few
hundred remote stations
Low noise receiver Forward Error Correction Electronic tuning over the frequency band Thermal management for high power over a wide temperature range
Usability
Configuration / diagnostics via front panel Management Port USB interface, Ethernet interface Built-in webserver SuperVisor with full configuration, diagnostics and monitoring functionality,
including remote station configuration / diagnostics over the radio link
LED display for on-site diagnostics Dedicated alarm port Software upgrade and diagnostic reporting via the host port USB flash drive Over-the-air software distribution and upgrades Simple installation with integrated mounting holes for wall, DIN rail and rack shelf mounting
22 | About the Radio
Modulation
FEC Coding
Capacity
QPSK (Low Gain)
Min Coded FEC
Minimum
16QAM (Low Gain)
Min Coded FEC
64QAM (Low Gain)
Min Coded FEC
Maximum
Modulation
FEC Coding
Coverage
QPSK (Low Gain)
Min Coded FEC
Maximum
16QAM (Low Gain)
Min Coded FEC
64QAM (Low Gain)
Min Coded FEC
Minimum
System Gain vs FEC Coding
Minimum FEC coding results in lower system gain, lower coverage but higher capacity.
This table defines the modulation order based on gross capacity:
This table defines the modulation order based on receiver sensitivity:
About the Radio | 23
Architecture
The Aprisa SRi Architecture is based around a layered TCP/IP protocol stack:
Physical
Proprietary wireless RS-232 and Ethernet interfaces
Link
Proprietary wireless (channel access, ARQ, segmentation) VLAN aware Ethernet bridge
Network
Standard IP Proprietary automatic radio routing table population algorithm
Transport
TCP, UDP
Application
HTTPS web management access through base station with proprietary management application software including management of remote stations over the radio link
SNMPv1/2/3 for network management application software
Product Operation
There are three components to the wireless interface: the Physical Layer (PHY), the Data Link Layer (DLL) and the Network Layer. These three layers are required to transport data across the wireless channel in the Point-to-Multipoint (PMP) configuration. The Aprisa SRi DLL is largely based on the 802.15.4 Media Access Control (MAC) layer using a proprietary implementation.
Physical Layer
The Aprisa SRi PHY uses a one frequency half duplex transmission mode which eliminates the need for a duplexer.
Remote nodes are predominantly in receive mode with only sporadic bursts of transmit data. This reduces power consumption.
The Aprisa SRi is a packet based radio. Data is sent over the wireless channel in discrete packets / frames, separated in time. The PHY demodulates data within these packets with coherent detection.
The Aprisa SRi PHY provides carrier, symbol and frame synchronization predominantly through the use of preambles. This preamble prefixes all packets sent over the wireless channel which enables fast Synchronization.
24 | About the Radio
Data Link Layer / MAC layer
The Aprisa SRi PHY enables multiple users to be able to share a single wireless channel; however a DLL is required to manage data transport. The two key components to the DLL are channel access and hop by hop transmission.
Channel Access
The Aprisa SRi radio uses a channel access of Access Request. Channel access scheme where the base stations controls the communication on the channel. Remotes ask for access to the channel, and the base station grants access if the channel is not occupied.
Access Request
This scheme is particularly suited to digital SCADA systems where all data flows through the base station. In this case it is important that the base station has contention-free access as it is involved in every transaction. The channel access scheme assigns the base station as the channel access arbitrator and therefore inherently it has contention-free access to the channel. This means that there is no possibility of contention on data originating from the base station. As all data flows to or from the base station, this significantly improves the robustness of the system.
All data messages are controlled via the AG (access grant) control message and therefore there is no possibility of contention on the actual end user data. If a remote station accesses the channel, the only contention risk is on the AR (access request) control message. These control messages are designed to be as short as possible and therefore the risk of collision of these control messages is significantly reduced. Should collisions occur these are resolved using a random back off and retry mechanism.
As the base station controls all data transactions multiple applications can be effectively handled, including a mixture of polling and report by exception.
About the Radio | 25
Hop by Hop Transmission
Hop by Hop Transmission is realized in the Aprisa SRi by adding a MAC address header to the packet. For
802.15.4, there are 2 addresses, the source and destination addresses.
Adaptive Coding and Modulation
The Aprisa SRi provides Adaptive Coding and Modulation (ACM) which maximizes the use of the RF path to provide the highest radio capacity available.
ACM automatically adjusts the modulation coding and FEC code rate in the remote to base direction of transmission over the defined modulation range based on the signal quality for each individual remote radio.
When the RF path is healthy (no fading), modulation coding is increased and the FEC code rate is decreased to maximize the data capacity.
If the RF path quality degrades, modulation coding is decreased and the FEC code rate is increased for maximum robustness to maintain path connectivity.
26 | About the Radio
Network Layer
Packet Routing
Aprisa SRi is a standard static IP router which routes and forwards IP packet based on standard IP address and routing table decisions.
Aprisa SRi router mode (see figure below), enables the routing of IP packets within the Aprisa SRi wireless network and in and out to the external router / IP RTUs devices connected to the Aprisa SRi wired Ethernet ports.
Within the Aprisa SRi Router mode, each incoming Ethernet packet on the Ethernet port is stripped from its Ethernet header to reveal the IP packet and to route the IP packet based on its routing table. If the destination IP address is one of the RTUs, the packet is then forwarded to the wireless ports and broadcasted as a PMP wireless packet to all the remote stations. The appropriate remote then routes the IP packet and forwards it based on its routing table to the appropriate Ethernet port, encapsulating the appropriate next hop MAC header and forwarding it to the RTU. The RTU can then interpret and process the IP data and communication is established between the RTU and the initiating communication device.
About the Radio | 27
Static IP Router
The Aprisa SRi works in the point-to-multipoint (PMP) network as a standard static IP router with the Ethernet and wireless / radio as interfaces and serial ports using terminal server as a virtual interface.
The Aprisa SRi static router is semi-automated operation, where the routing table is automatically created in the base station and populated with routes to all remote stations in the network during the registration process and vice versa, where the routing table is automatically created in remote stations and populated with routes to base station during the registration process. Updates occur when remote is disconnected from network for any reason, with the routing table updated in a controlled fashion.
Also, in decommission operation, the base station routing tables are completely flushed allowing an automatic rebuild. This avoids the user manually inserting / removing of multiple static routes to build / change the routes in the network which might be tedious and introduce significant human error. The Aprisa SRi works as a static IP router without using any routing protocol and therefore does not have the overhead of a routing protocol for better utilization of the narrow bandwidth network.
In addition to the semi-automated routes, the user can manually add / remove routes in the routing table for the radio interface, Ethernet Interface and for routers which are connected to the radio network.
The Aprisa SRi base station is used as a gateway to other networks. Thus, a configurable IP address default gateway can be set using a static route in the routing table with a destination IP address of the destination network address. It is recommended to use a real network IP address (actual device IP) for the gateway and not 0.0.0.0.
The Aprisa SRi sub-netting rules distinguish between the wireless interface and the remote Ethernet interface where RTUs are connected. The entire wireless network is set on a single IP subnet, while each Aprisa SRi remote’s Ethernet interface is set to a different subnet network. In this way, the user can easily distinguish between the remotes subnet IP addresses.
28 | About the Radio
Destination Address
Destination Mask
Gateway Address
Static Route Setting at ?
192.168.3.0
255.255.255.0
192.168.2.1
Base station
192.168.3.0
255.255.255.0
192.168.2.2
Remote station
The Radio Network as a Gateway Router
The Aprisa SRi point-to-multipoint radio network can be considered as a gateway router where the ‘network Ethernet interface’ on each radio in the network is the ‘router port’.
The routing table for all directly attached devices to the Aprisa SRi network, at the Base or the Remote stations is automatically built and no static routes are required to be entered for those device routes.
The ‘Radio interface IP address’ is used internally for the radio network and automatic routes. It is not used when setting static routes or default gateways.
Static route IP addresses or the default gateway should use the ‘network Ethernet interface’ IP address.
External network routers should be set with a high metric for the SRi path, to prevent route updates being sent over the radio network.
The Radio Network as a Router – Example
The purpose of this example is to determine the static route setting for router R2 in the base station and remote station in the following network.
Since the Aprisa SRi network should be considered as a router where the network Ethernet interface is the ‘router port’, the network configuration for setting the static routes or the default gateway IP addresses is described in the follow figure:
Thus, the static route setting for router R2 at the Aprisa SRi base station and remote station will be:
Note: The radio network (base station and remote stations) will automatically build routes to the attached device e.g. SCADA Master station or attached router e.g. router R1 so static routes are not required for these devices.
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