1 Wireless Communications for SCADA Systems BCWWA 2008
Wireless Data Communications
for SCADA Systems
2 Wireless Communications for SCADA Systems BCWWA 2008
Advanced SCADA Features
Networking (Communication Anywhere to Anywhere)
Data Reliability (No Communication Errors)
Data Security (Immune to Intrusion)
Communication
Network
3 Wireless Communications for SCADA Systems BCWWA 2008
“Open” Communication Solutions
Versatile IEDs
• Pressure Control
• Flow calculations
• Pumps Start
• etc.
SCADA
• Wonderware • Intellution • Factorylink • etc.
• 900 Mhz Conventional
• 900MHz S.Spectrum
• Analog Trunking
• VHF / UHF Conventional
• UHF-900 MHz MAS System
• Telco Network
• GSM/GPRS
• Satellite
• Microwave…….
Versatile
Interface
• MODBUS • DNP 3.0 • OPC • MDLC over TCP/IP • etc.
Versatile
Media
Applications
• Pressure/Flow • Maintenance • Leak detection • etc.
PLC Interface
• Allen Bradley
• Modicon
• Etc.
4 Wireless Communications for SCADA Systems BCWWA 2008
A Communication Oriented RTU 1/3
Programmable Controller
Communication Modem,
Remote
Control
Local
Control
A powerful combination of two functions:
– Programmable Logic Controller
– Communication Modem
5 Wireless Communications for SCADA Systems BCWWA 2008
A Communication Oriented RTU 2/3
Local
Control of
Remote
Sites
Reporting
By
Event
Node
Linking
two Media
Protocol
Converter
for PLC
Links
Store and
Forward
Repeater
F1-F1
Time
Synchroniz
ation
RTU
6 Wireless Communications for SCADA Systems BCWWA 2008
A Communication Oriented RTU 3/3
Local
Process
Network
Comm.
++
+++
-
+
Polling
via radio
Report
by Event
PLC
RTU
7 Wireless Communications for SCADA Systems BCWWA 2008
“Store and Forward” Links
S&F
FIU
All radio links may use the same frequency !
S&F Repeater
RTU
RTU
RTU
SCADA HMI
8 Wireless Communications for SCADA Systems BCWWA 2008
Backup Links Enhance Reliability
IP Gateway
Damaged Wire-line
Backup Radio
RF
SCADA Control Center
Line
RF
RTU
Radio
RTU
RTU
RTU RF
9 Wireless Communications for SCADA Systems BCWWA 2008
Wide Area SCADA-Data Network
ToolBox
Primary
Water SCADA
Secondary
MCC
Ethernet
Ethernet
IP
Gateway Line Based
network
S&F
Repeater
RTU and
Comm. Node
RTU for
Pumping Station
RTU for
Reservoir
IP
S&F
Repeater
10 Wireless Communications for SCADA Systems BCWWA 2008
Complex SCADA System
Main
ToolBox
Primary
MCC
Secondary
MCC
Remote Ethernet
Local Ethernet
IP Gateway Line
Based IP
RTU & Data
Comm. Node
Remote
ToolBox
Wireline Comm.
RTU & Data
Comm.
S&F
RTU & Data
Comm. Node
(SLIP)
Wireline
Comm.
RTU & Data
Comm. Node
RTU & Data
Comm. Node Prime Link
Backup
Link
Prime Link
Prime Link
Printer
Backup
Link
TS
11 Wireless Communications for SCADA Systems BCWWA 2008
Reporting in Wireless SCADA Systems
• Cyclic Polling of RTUs – Complete Polling - “Tell me about all your conditions”
• Time consuming process not suitable for wireless media
– Report by Exception – “Tell me about only what changed”
• Change of state that does not require immediate attention
– Cyclic Health Check - “Indicate shortly that you are alive”
• To minimize the health check cycle (leave time gaps for alarms)
• Initiating Unsolicited Messages – Report By Event - Predefined Alarm conditions
• Must get immediate attention of the operator (critical alarms)
• Group Calls – Burst messages – “Everyone Accept this Message”
• No acknowledgement is expected (“all keep quite for 5 minutes”)
12 Wireless Communications for SCADA Systems BCWWA 2008
Multiple Address System Network
Site 2
SCADA
Site 1
Remote Programming
F2
F1
F2
F1
Using the 7-Layer
protocol sites may
be configured for
single frequency F3
F3
F3 F3
F3
RTU RTU
RTU
RTU
F1 F2
13 Wireless Communications for SCADA Systems BCWWA 2008
Wireless IP Connection with SCADA
Master
Control
Center
Programming
ToolBox
IP
Network Ethernet
Wireless IP Infrastructure
IP
Gateway
IP Con.
IP Con.
RTU
IP Con.
IP Con.
Programming
STS
IP Con.
RTU
900 MHz – 5.7 GHz
RTU
14 Wireless Communications for SCADA Systems BCWWA 2008
Wireless GSM/GPRS Network
Site 4
Site 1
Site 2
Site 3
SCADA
Micro Wave
Back Bone
Voice Voice
Voice
RTU
RTU RTU
RTU
15 Wireless Communications for SCADA Systems BCWWA 2008
Combined PLC and I/Os with RTU
Wireless
Network
Customer Site
RTU With radio
STS
ToolBox
I/O
Control
Installed PLC or IED
I/O
Control
PLC or IED
with Native
protocol
16 Wireless Communications for SCADA Systems BCWWA 2008
SCADA Security Incident Trends
5
12 2 2 3
4
1
6
13
28
18
6
1982
- 19
93
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
Sep
t. 20
05
* Projected
20* 22*
Something Big
Changes Here
Source: Eric Byres
17 Wireless Communications for SCADA Systems BCWWA 2008
Combined Set of Solutions May Help
• Physical Security – Provide adequate security to remote sites
• Firewalls – Protecting the corporate network
• Use of private data network – Public networks are often vulnerable
• Use of “complex” protocol structure – Need for specific analyzer
• Communications Security – Combined Encryption and Authentication
– Multiple passwords across the system, etc.
IP Gateway
Master Control Center
18 Wireless Communications for SCADA Systems BCWWA 2008
Cost Saving Analysis 1/2
• Calculate the overall Economic factors:
– Cost of lost potable water due to bursts and leakages
– Cost of electric energy during designated period
– Cost for repairs and replacement of equipment
– Cost travel to remote sites for periodic checkup
– Cost of system supervision and manual data collection
Cost (without SCADA) – Cost (with SCADA)
Saving = -------------------------------------------------------------- (%) Cost (without SCADA)
19 Wireless Communications for SCADA Systems BCWWA 2008
Cost Saving Analysis 2/2
0
500
1000
1500
2000
2500
Without SCADA With SCADA
Cost of lost potable water due to
bursts and leakages
Cost of electric energy during
designated period
Cost for repairs and replacement
of equipment
Cost travel to remote sites for
periodic checkup
Cost of manual data collection
Total
20 Wireless Communications for SCADA Systems BCWWA 2008
With Simple Protocol
• Network Addressing
• Error Detection
& Message Retry
• Diagnostics
• Data Security
• Main Application
With Layered Protocol
•Built In
•Built In
•Built In
•Built In
• Main Application
System Programming Tasks