10 Communication
PCS-978 Transformer Relay
10-1
Date: 2013-01-16
10.1 Overview
This section outlines the remote communications interfaces of NR equipment. The protective
device supports a choice of three protocols via the rear communication interface (RS-485 or
Ethernet), selected via the model number by setting. The protocol provided by the protective
devic
e is indicated in the submenu in the “
Communication Settings
” column. Using the keypad
and LCD, set the parameter [Protocol_RS485A] and [Protocol_RS485B], the corresponding
protocol will be selected.
The rear EIA RS-485 interface is isolated and is suitable for permanent connection of whichever
protocol is selected. The advantage of this type of connection is that up to 32 protective devices
can be “daisy chained” together using a simple twisted pair electrical connection.
It should be noted that the descriptions contained within this section do not aim to fully detail the
protocol itself. The relevant documentation for the protocol should be referred to for this
information. This section serves to describe the specific implementation of the protocol in the relay.
10.2 Rear Communication Port Information
10.2.1 RS-485 Interface
This protective device provides two rear RS-485 communication ports, and each port has three
terminals in the 12-terminal screw connector located on the back of the relay and each port has a
ground terminal for the earth shield of the communication cable. Please refer to the section of
“Communication Interface module” for details of the connection terminals. The rear ports provide
RS-485 serial data communication and are intended for use with a permanently wired connection
to a remote control center.
10.2.1.1 EIA RS-485 Standardized Bus
The EIA RS-485 two-wire connection provides a half-duplex fully isolated serial connection to the
product. The connection is polarized and whilst the product’s connection diagrams indicate the
polarization of the connection terminals it should be borne in mind that 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.
10.2.1.2 Bus Termination
The EIA RS-
485 bus must have 120Ω (Ohm) ½ Watt terminating resistors fitted at either end
across the signal wires (refer to
. Some devices may be able to provide the bus
terminating resistors by different connection or configuration arrangements, in which case
separate external components will not be required. However, this product does not provide such a
facility, so if it is located at the bus terminus then an external termination resistor will be required.
Summary of Contents for PCS-978
Page 1: ...PCS 978 Transformer Relay Instruction Manual NR Electric Co Ltd ...
Page 2: ......
Page 6: ...Preface PCS 978 Transformer Relay IV Date 2013 01 16 ...
Page 10: ...Preface PCS 978 Transformer Relay VIII Date 2013 01 16 ...
Page 62: ...3 Operation Theory PCS 978 Transformer Relay 3 p Date 2013 01 16 ...
Page 250: ...4 Supervision PCS 978 Transformer Relay 4 b Date 2013 01 16 ...
Page 264: ...4 Supervision PCS 978 Transformer Relay 4 14 Date 2013 01 16 ...
Page 266: ...5 Management PCS 978 Transformer Relay 5 b Date 2013 01 16 ...
Page 272: ...5 Management PCS 978 Transformer Relay 5 6 Date 2013 01 16 ...
Page 334: ...6 Hardware Description PCS 978 Transformer Relay 6 60 Date 2013 01 16 ...
Page 370: ...8 Human Machine Interface PCS 978 Transformer Relay 8 d Date 2013 01 16 ...
Page 404: ...8 Human Machine Interface PCS 978 Transformer Relay 8 34 Date 2013 01 16 ...
Page 406: ...9 Configurable Function PCS 978 Transformer Relay 9 b Date 2013 01 16 ...
Page 446: ...10 Communication PCS 978 Transformer Relay 10 26 Date 2013 01 16 ...
Page 448: ...11 Installation PCS 978 Transformer Relay 11 b Date 2012 10 09 ...
Page 456: ...11 Installation PCS 978 Transformer Relay 11 8 Date 2012 10 09 ...
Page 458: ...12 Commissioning PCS 978 Transformer Relay 12 b Date 2012 12 07 ...
Page 468: ...12 Commissioning PCS 978 Transformer Relay 12 10 Date 2012 12 07 ...
Page 470: ...13 Maintenance PCS 978 Transformer Relay 13 b Date 2012 10 09 ...
Page 474: ...13 Maintenance PCS 978 Transformer Relay 13 4 Date 2012 10 09 ...
Page 476: ...14 Decommissioning and Disposal PCS 978 Transformer Relay 14 b Date 2012 10 09 ...
Page 478: ...14 Decommissioning and Disposal PCS 978 Transformer Relay 14 2 Date 2012 10 09 ...
Page 480: ...15 Manual Version History PCS 978 Transformer Relay 15 2 Date 2013 01 16 ...