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OPERATING PRINCIPLES
2.5 INPUTS AND OUTPUTS
2.5.1 DIGITAL INPUTS
The DFF family of relays can have a variety of digital inputs. For details see ordering code in section 5 - MODEL
LIST. The minimum number of inputs is 7 and the maximum is 14 (two groups of 7 Inputs each with a common
terminal for each group). See chapter 4 for details on advanced configuration options.
2.5.2 OUTPUTS
The DFF family of relays provides a variety of digital outputs. For details see ordering code in section 5 - MODEL
LIST. The minimum number of outputs is 13 and the maximum is 33. Four outputs are pre-assigned to the protection
function trips and one for the internal alarm. See chapter 4 for details on advanced configuration options.
2.6 MAN MACHINE INTERFACE (MMI).
The DFF relay includes a 20-button keypad with a two-line LCD display (16 characters per line). The background of
the LCD is back lit by LEDs. The contrast can be adjusted through a trimmer accessible behind the front board.
Through this interface, the user can change settings, visualize actual values, etc. Refer to KEYPAD AND DISPLAY
section.
2.7 REMOTE COMMUNICATIONS
The relay has up to 3 serial communications ports. PORT 1 is accessible at the front of the relay PORTs 2 and 3 are
accessed at the rear of the relay.
There are different models depending on the physical media of connector PORT 2 (RS-232, RS-485 or fiber optics).
See ordering code at section 5 - MODEL LIST.
The connector for PORT1 has priority over connector port2 and is selected once DCD signal (Data Carrier Detect) is
activated. See figure 8 for required connections. Use the cable configuration described in the figure or use a standard
direct RS-232 cable (no crossings) and a standard Null-Modem adaptor.
PORTS 1 and 2 are fully independent and can be used at the same time. PORT 3 is switched with PORT 1.
The relay is in local communication when using either the MMI or the front port.
Both local and remote communication can be active at the same time, however the possibility of changing settings or
performing control operations is limited only to the communication mode with higher priority (local mode). The other
channel then will only have access to read the information.
Once the local communication is interrupted, either by the disconnection of port 1 connector or by returning the MMI
to the initial screen (done manually pressing CLR key or automatically after 15 minutes without any button being
pressed), the remote communication mode recovers its lost privileges of being able to change settings or perform
control operations.
14
DFF Digital Feeder Relay
GEK-106166E
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