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GEK – 106166B
2.7 MAN MACHINE INTERFACE (MMI).
The DFF relay includes a 20-button keypad with a two-line screen (16 characters per line). The screen has
background light by LED diodes (the brightness can be adjusted through a power meter accessible at the back of
the front board).
Through this interface, the user can change settings, visualize actual values, access the stored information, etc.
The description of how to perform these operations is described in the KEYPAD AND DISPLAY section of this
book.
2.8 REMOTE COMMUNICATIONS
The relay has two serial communications ports. Port 1 is accessible at the relay front through a DB9 connector 1
(PORT1). Port 2 is accessed at the relay back through another connector (PORT 2).
There are different models depending on the physical media of connector PORT 2 (RS-232, RS-485 or fiber
optics). In models "only RS232" all connectors are RS232. For models "RS232 and fiber optics" or "RS-232 and
RS-485", connector PORT1 is RS232 while PORT2 is either a fiber optics connector or a RS-485 one.
Connector for PORT1 has priority above connector PORT2 and is selected once DCD signal (Data Carrier
Detect) is activated. In figure 3 there is a sketch of how to make a connection to a personal computer.
Ports 1 and 2 are fully independent and can be used at the same time.
The relay is in local communication when we are using either the MMI or the front port and in remote
communication every time we use the rear port.
Both types of 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 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 on purpose 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.
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