GE DBF, Instructions Manual

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2. OPERATION LOGIC
16 DBF Breaker Failure Protection GEK-106168E
2.6. REMOTE COMMUNICATIONS
The relay has 2 serial gates and three connectors. Gate 1 can be reached from the front of the relay in connector
1 (PORT 1 connector) or from the rear (PORT 2 connector). The second gate can be reached from connector 3
(PORT 3 connector) which is located on the rear.
There are different models, each with a different physical connection for the PORT 3 connector (RS-232/RS-485
or fiber-optic). In the "RS232" models the three connectors are RS232. In the "RS232 and fiber-optic" models the
PORT1 and PORT2 connectors are RS232 while the PORT3 connector is replaced by a fiber-optic connector.
The PORT 1 connector has priority over the PORT 2 connector and is selected when the DCD (Data Carrier
Detect) signal is activated. Figure 8 shows how to make the connections to a personal computer.
Gate 1 (PORT 1 and PORT 2 connectors) and 2 (PORT 3 connector) are independent and the unit can serve
them simultaneously.
The communications protocol is the same used for the rest of the GE digital protection systems and requires the
use of the GE-LOCAL software. PORT 3 protocol can be chosen between M-LINK and ModBus RTU. The
protocol is highly reliable and allows communication with different protection systems. It guarantees very efficient
data transfer (especially for the oscillography and other large files) along with error detection and automatic
communication recovery.
The status of the local/remote communication is indicated on the front of the unit by LED indicator 16 (the last LED
in the right-hand column, according to the default configuration.) Local communication refers to communication via
the keyboard/display (local display showing any information except for the initial DBF GENERAL ELECTRIC
screen), or via communications gate 1 (PORT 1, PORT2 connectors), and remote communication refers to
connection via gate 2 (PORT 3 rear connector).
Local and remote communications can exist at the same time, although there is only one possibility for changing
settings and carrying out operations, since this can only be done with the communication which has priority (local
communication) while the other is limited only to accessing information. When the local communication is
interrupted, either by the disconnection of PORT 1 connector or because the HMI is on the initial screen (a
situation which can be caused intentionally, or automatically if no key has been pressed for 15 minutes), the
remote communication recovers the ability to modify settings and carry out operations.