Technical data

36
1MRS751108-MUM
Protection Relay
Technical Reference Manual, General
REX 521
5.1.12. Serial communication
The protection relay has two serial communication ports, one on the front panel and
the other on the rear panel.
The connector located on the front panel is a standard ABB optical connector that is
intended to be used for setting the parameters of the protection relay. During the
transmission of the parameters, an interface cable is connected between the relay and
the standard RS-232 interface of a PC, running the Relay Setting Tool.
On the rear panel, there is a fibre-optic interface used to connect the protection relay
to a distribution automation system via SPA, LON, IEC 60870-5-103, Modbus or
DNP 3.0 bus.
There is also an isolated RS-485 connection (twisted pair) available for SPA,
Modbus and DNP 3.0 communication in connector X3.1:9,10. For the location of
the RS-485 connection on the rear panel, see “Terminal connections” on page 57.
The connection is marked with texts “Data A” and “Data B” on the panel.
The following table describes the combinations of different communication
protocols and the physical interfaces that can be used at the same time (X = in use).
5.1.12.1. Optical communication port on the rear panel
The fibre-optic interface on the rear panel contains two optical connectors, Tx
(X3.2) and Rx (X3.3). The connectors are used for interfacing the unit to an optical
fibre bus using either plastic fibre or glass fibre cables. See also Fig. 5.1.12.5.-2 on
page 38 for more information about the plastic and glass fibre cables.
The incoming optical fibre is connected to the receiver, input Rx, and the outgoing
optical fibre to the transmitter, output Tx. Special attention should be paid when
handling, mounting, and connecting fibre-optic cables. For additional information,
see the document 34 SPA 13 EN1
Plastic-core fibre-optic cables. Features and
instructions for mounting
.
The communication port supports five different protocols, SPA, LON,
IEC 60870-5-103, Modbus and DNP 3.0. The SPA, IEC_103, Modbus and DNP 3.0
protocols are always supported while LON is not available in all the relay variants.
The relay does not automatically recognize which bus it is connected to and
therefore the protocol must be set manually through the HMI or the Relay Setting
Tool (Main menu\Configuration\Communication\Rear port). For
rear port options, see Table 5.1.12.2-1.
Table 5.1.12-1 Protocol combinations and physical interfaces
Protocol Rear port (Optical) Rear port (RS-485)
Front connector
(SPA only)
SPA X X
SPA X X
LON X X
IEC_103 X X
Modbus X X
Modbus X X
DNP 3.0 X X
DNP 3.0 X X