
3
SERIAL COMMUNICATION
The physical layer standards that are used for serial communications for SCADA purposes are:
●
EIA(RS)485 (often abbreviated to RS485)
●
K-Bus (a proprietary customization of RS485)
EIA(RS)232 is used for local communication with the IED (for transferring settings and downloading firmware
updates).
RS485 is similar to RS232 but for longer distances and it allows daisy-chaining and multi-dropping of IEDs.
K-Bus is a proprietary protocol quite similar to RS485, but it cannot be mixed on the same link as RS485. Unlike
RS485, K-Bus signals applied across two terminals are not polarised.
It is important to note that these are not data protocols. They only describe the physical characteristics required
for two devices to communicate with each other.
For a description of the K-Bus standard see
(on page508) and General Electric's K-Bus interface guide
reference R6509.
A full description of the RS485 is available in the published standard.
3.1
EIA(RS)232 BUS
The EIA(RS)232 interface uses the IEC 60870-5 FT1.2 frame format.
The device supports an IEC 60870-5 FT1.2 connection on the front-port. This is intended for temporary local
connection and is not suitable for permanent connection. This interface uses a fixed baud rate of 19200 bps, 11-bit
frame (8 data bits, 1 start bit, 1 stop bit, even parity bit), and a fixed device address of '1'.
EIA(RS)232 interfaces are polarised.
3.2
EIA(RS)485 BUS
The RS485 two-wire connection provides a half-duplex, fully isolated serial connection to the IED. The connection is
polarized but there is no agreed definition of which terminal is which. If the master is unable to communicate with
the product, and the communication parameters match, then it is possible that the two-wire connection is
reversed.
The RS485 bus must be terminated at each end with 120 Ω 0.5 W terminating resistors between the signal wires.
The RS485 standard requires that each device be directly connected to the actual bus. Stubs and tees are
forbidden. Loop bus and Star topologies are not part of the RS485 standard and are also forbidden.
Two-core screened twisted pair cable should be used. The final cable specification is dependent on the application,
although a multi-strand 0.5 mm
2
per core is normally adequate. The total cable length must not exceed 1000 m. It
is important to avoid circulating currents, which can cause noise and interference, especially when the cable runs
between buildings. For this reason, the screen should be continuous and connected to ground at one end only,
normally at the master connection point.
The RS485 signal is a differential signal and there is no signal ground connection. If a signal ground connection is
present in the bus cable then it must be ignored. At no stage should this be connected to the cable's screen or to
the product’s chassis. This is for both safety and noise reasons.
It may be necessary to bias the signal wires to prevent jabber. Jabber occurs when the signal level has an
indeterminate state because the bus is not being actively driven. This can occur when all the slaves are in receive
mode and the master is slow to turn from receive mode to transmit mode. This may be because the master is
waiting in receive mode, in a high impedance state, until it has something to transmit. Jabber causes the receiving
device(s) to miss the first bits of the first character in the packet, which results in the slave rejecting the message
and consequently not responding. Symptoms of this are; poor response times (due to retries), increasing message
error counts, erratic communications, and in the worst case, complete failure to communicate.
P446SV
Chapter 21 - Communications
P446SV-TM-EN-1
507
Содержание MiCOM P40 Agile
Страница 2: ......
Страница 24: ...Contents P446SV xxii P446SV TM EN 1 ...
Страница 33: ...CHAPTER 1 INTRODUCTION ...
Страница 34: ...Chapter 1 Introduction P446SV 2 P446SV TM EN 1 ...
Страница 46: ...Chapter 1 Introduction P446SV 14 P446SV TM EN 1 ...
Страница 47: ...CHAPTER 2 SAFETY INFORMATION ...
Страница 48: ...Chapter 2 Safety Information P446SV 16 P446SV TM EN 1 ...
Страница 60: ...Chapter 2 Safety Information P446SV 28 P446SV TM EN 1 ...
Страница 61: ...CHAPTER 3 HARDWARE DESIGN ...
Страница 62: ...Chapter 3 Hardware Design P446SV 30 P446SV TM EN 1 ...
Страница 88: ...Chapter 3 Hardware Design P446SV 56 P446SV TM EN 1 ...
Страница 89: ...CHAPTER 4 SOFTWARE DESIGN ...
Страница 90: ...Chapter 4 Software Design P446SV 58 P446SV TM EN 1 ...
Страница 101: ...CHAPTER 5 CONFIGURATION ...
Страница 102: ...Chapter 5 Configuration P446SV 70 P446SV TM EN 1 ...
Страница 124: ...Chapter 5 Configuration P446SV 92 P446SV TM EN 1 ...
Страница 125: ...CHAPTER 6 SAMPLED VALUE OPERATION ...
Страница 126: ...Chapter 6 Sampled Value Operation P446SV 94 P446SV TM EN 1 ...
Страница 136: ...Chapter 6 Sampled Value Operation P446SV 104 P446SV TM EN 1 ...
Страница 137: ...CHAPTER 7 DISTANCE PROTECTION ...
Страница 138: ...Chapter 7 Distance Protection P446SV 106 P446SV TM EN 1 ...
Страница 196: ...Chapter 7 Distance Protection P446SV 164 P446SV TM EN 1 ...
Страница 197: ...CHAPTER 8 CARRIER AIDED SCHEMES ...
Страница 198: ...Chapter 8 Carrier Aided Schemes P446SV 166 P446SV TM EN 1 ...
Страница 240: ...Chapter 8 Carrier Aided Schemes P446SV 208 P446SV TM EN 1 ...
Страница 241: ...CHAPTER 9 NON AIDED SCHEMES ...
Страница 242: ...Chapter 9 Non Aided Schemes P446SV 210 P446SV TM EN 1 ...
Страница 256: ...Chapter 9 Non Aided Schemes P446SV 224 P446SV TM EN 1 ...
Страница 257: ...CHAPTER 10 POWER SWING FUNCTIONS ...
Страница 258: ...Chapter 10 Power Swing Functions P446SV 226 P446SV TM EN 1 ...
Страница 281: ...CHAPTER 11 AUTORECLOSE ...
Страница 282: ...Chapter 11 Autoreclose P446SV 250 P446SV TM EN 1 ...
Страница 376: ...Chapter 11 Autoreclose P446SV 344 P446SV TM EN 1 ...
Страница 377: ...CHAPTER 12 CB FAIL PROTECTION ...
Страница 378: ...Chapter 12 CB Fail Protection P446SV 346 P446SV TM EN 1 ...
Страница 389: ...CHAPTER 13 CURRENT PROTECTION FUNCTIONS ...
Страница 390: ...Chapter 13 Current Protection Functions P446SV 358 P446SV TM EN 1 ...
Страница 416: ...Chapter 13 Current Protection Functions P446SV 384 P446SV TM EN 1 ...
Страница 417: ...CHAPTER 14 VOLTAGE PROTECTION FUNCTIONS ...
Страница 418: ...Chapter 14 Voltage Protection Functions P446SV 386 P446SV TM EN 1 ...
Страница 431: ...CHAPTER 15 FREQUENCY PROTECTION FUNCTIONS ...
Страница 432: ...Chapter 15 Frequency Protection Functions P446SV 400 P446SV TM EN 1 ...
Страница 438: ...Chapter 15 Frequency Protection Functions P446SV 406 P446SV TM EN 1 ...
Страница 439: ...CHAPTER 16 MONITORING AND CONTROL ...
Страница 440: ...Chapter 16 Monitoring and Control P446SV 408 P446SV TM EN 1 ...
Страница 476: ...Chapter 16 Monitoring and Control P446SV 444 P446SV TM EN 1 ...
Страница 477: ...CHAPTER 17 SUPERVISION ...
Страница 478: ...Chapter 17 Supervision P446SV 446 P446SV TM EN 1 ...
Страница 490: ...Chapter 17 Supervision P446SV 458 P446SV TM EN 1 ...
Страница 491: ...CHAPTER 18 DIGITAL I O AND PSL CONFIGURATION ...
Страница 492: ...Chapter 18 Digital I O and PSL Configuration P446SV 460 P446SV TM EN 1 ...
Страница 504: ...Chapter 18 Digital I O and PSL Configuration P446SV 472 P446SV TM EN 1 ...
Страница 505: ...CHAPTER 19 FIBRE TELEPROTECTION ...
Страница 506: ...Chapter 19 Fibre Teleprotection P446SV 474 P446SV TM EN 1 ...
Страница 522: ...Chapter 19 Fibre Teleprotection P446SV 490 P446SV TM EN 1 ...
Страница 523: ...CHAPTER 20 ELECTRICAL TELEPROTECTION ...
Страница 524: ...Chapter 20 Electrical Teleprotection P446SV 492 P446SV TM EN 1 ...
Страница 534: ...Chapter 20 Electrical Teleprotection P446SV 502 P446SV TM EN 1 ...
Страница 535: ...CHAPTER 21 COMMUNICATIONS ...
Страница 536: ...Chapter 21 Communications P446SV 504 P446SV TM EN 1 ...
Страница 606: ...Chapter 21 Communications P446SV 574 P446SV TM EN 1 ...
Страница 607: ...CHAPTER 22 CYBER SECURITY ...
Страница 608: ...Chapter 22 Cyber Security P446SV 576 P446SV TM EN 1 ...
Страница 625: ...CHAPTER 23 INSTALLATION ...
Страница 626: ...Chapter 23 Installation P446SV 594 P446SV TM EN 1 ...
Страница 637: ...CHAPTER 24 COMMISSIONING INSTRUCTIONS ...
Страница 638: ...Chapter 24 Commissioning Instructions P446SV 606 P446SV TM EN 1 ...
Страница 695: ...CHAPTER 25 MAINTENANCE AND TROUBLESHOOTING ...
Страница 696: ...Chapter 25 Maintenance and Troubleshooting P446SV 664 P446SV TM EN 1 ...
Страница 712: ...Chapter 25 Maintenance and Troubleshooting P446SV 680 P446SV TM EN 1 ...
Страница 713: ...CHAPTER 26 TECHNICAL SPECIFICATIONS ...
Страница 714: ...Chapter 26 Technical Specifications P446SV 682 P446SV TM EN 1 ...
Страница 741: ...APPENDIX A ORDERING OPTIONS ...
Страница 742: ...Appendix A Ordering Options P446SV P446SV TM EN 1 ...
Страница 744: ...Appendix A Ordering Options P446SV A2 P446SV TM EN 1 ...
Страница 745: ...APPENDIX B SETTINGS AND SIGNALS ...
Страница 746: ...Appendix B Settings and Signals P446SV P446SV TM EN 1 ...
Страница 954: ...Appendix B Settings and Signals P446SV B208 P446SV TM EN 1 ...
Страница 955: ...APPENDIX C WIRING DIAGRAMS ...
Страница 956: ...Appendix C Wiring Diagrams P446SV P446SV TM EN 1 ...
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