Transcript Document
ANALOGUE vs DIGITAL RADIO SYSTEMS Networks for Telemetry Applications Where are Data Radio Systems Used? • • • • Wide area networks for machine to machine data communications. Remote monitoring and control of industrial systems. Remote logging and reporting to SCADA and MES systems. Security and remote access systems. Telemetry System Model SCADA SYSTEM CONTROL CENTRE HUMAN INTERFACE & DATA MANAGEMENT Communications Network SEWAGE & WASTE STATUS POINTS & ALARMS METERING STATIONS LOGGED DATA & ALARMS TELEMETRY NETWORK BULK WATER SUPPLY MONITORING & CONTROL Analogue Radio Network Topology Remote Station Radio Modem Distant Stations RTU SCADA Master Station Remote Station Radio Modem Radio Repeater Radio Modem RTU Features of Analogue Radio Systems • Analogue Radio Systems – Can cover large distances with repeaters – Slow over the air data rate – max 1200baud – Requires additional interface module between radio and device – Serial to FSK converter – Radio requires unique alignment for each device interface – Cannot just be swapped out on service/replacement – No management available on radio network – High maintenance on radios – routine tuning – Lower cost of deployment – analogue radios are cheaper Digital Radio Network Topology Remote Station Radio Modem Distant Stations RTU SCADA Remote Station Radio Repeater Master Station Radio Modem Radio Modem RTU Features of Digital Radio Systems • Digital Radio Systems – Can cover large distances with repeaters – Fast over the air data rate – Typically 9600baud but can go up to 19200baud – Better sensitivity – typical -112dBm @ 9600baud – Does not require additional interface module between radio and device – Direct Serial or Ethernet interface to the radio – Radio does not require alignment for device interface – Plug & Play for replacement/service – Comprehensive management software for radio networks – Diagnostics, configuration, interface to other environments (SCADA) – No maintenance on radios – no routine tuning – Higher cost of deployment – digital radios are more expensive Time of Flight Comparison Analogue vs Digital Radio 960bits Data Packet 3000 Base Station Repeater #1 Repeater #2 Time (ms) 2500 Analogue @ 1200baud 2000 Digital @ 9600baud 1500 1000 500 0 PreEmp DeEmp PreEmp DeEmp PreEmp Transmission Stage DeEmp Data Total Comparison Summary Analogue Radio Digital Radio 8x Faster Supports repeater networks Supports repeater networks Max 1200baud over the air data rate Max 19200baud over the air data rate Requires additional interface to device Direct interface for Serial/Ethernet devices Routine alignment and tuning Once off setup, no routine maintenance No “in band” remote management Comprehensive network management tools Lower costs of deployment Higher cost of deployment Higher cost of maintenance Low cost of maintenance