Practical_modern_SCADA_protocols_-_dnp3,_60870-5_and_Related_Systems

536 Index
Modbus protocol (Continued)
preset single register, 53
read coil/digital output status, 49
read digital input status, 50
read exception status, 53–4
read holding registers, 50–1
reading input registers, 51–2
specifics, 47
synchronization, 48
Network time protocol (NTP), 337
Open standards:
development, 64
DNP 3.0/IEC 870 protocols, 65
early, 64
interoperability, 63
immediate benefits, 63–4
long-term benefits, 64
realizing benefits, 64
Open systems interconnection (OSI), 4–5,
56–9, 335
seven layer model, 5, 10, 73–6
application, 6, 60
data link, 6, 62
network, 6, 61
physical, 6, 62
presentation, 6, 60
session, 6, 60
transport, 6, 60–1
PID control, 2
Port Hedland TWS System see water industry
Post office protocol (POP3), 337
Pressure reading valve (PRV), 369, 370
Profibus, 14, 349
application layer, 352
communication model, 352–3
application services, 353–4
communication relationship list (CRL),
354
lower layer interface (LLI), 354
network management, 354
profiles, 354–5
data link layer, 351
physical layer, 350–1
Profibus, 2
Programme logic controller (PLC), 25
Protocols, 42
error control/flow control, 45
HDLC, 42–3
frame contents, 44
frame format, 43
Modbus, 45–56
operation, 44
see also distributed network protocol (DNP3);
TCP/IP protocol
Remote login (RLOGIN), 337
Remote procedure calls (RPC), 337
Remote terminal units (RTUs), 18, 19–20, 369
Analog input modules, 21–2
Analog output modules, 22–3
communication interfaces, 24–5
communication with another RTU, 34
control processor unit (CPU), 21
data mapping, 380
digital counter/accumulator modules, 23–4
digital output module, 24
DNP3 configuration, 381–90
PDS, 377–9
PLCs used as, 25
power supply odule, 25
standards, 35–42
RTUs see remote terminal units
SCADA systems, 1–2, 362, 365, 369, 372
(dis)advantages, 2
PLC/DCS, 14
future developments, 391–2
hardware, 3–4, 15–16
history, 12
LANs, 17
modem use, 18
modern, 13–15
sensor to panel type, 13
software, 4, 16–17
water industry application, 374–90
Session protocol data unit (SPDU), 75
Signal quality error (SQE), 319, 332
Simple mail transfer protocol (SMTP), 337
Slot time, 34–5
Standards, 35
RS-232, 35–6
electrical signal characteristics, 36–7
interchange circuits, 38–9
interface mechanical characteristics, 38
RS-485, 41–2
sequence of asynchronous operation, 39–41
synchronous communications, 41
Synchronization process:
clock, 270, 294–6, 306
acquisition of transmission delay, 295–6
communication, 41
data signal rate selector, 41
RS-232, 41