Programmable Function Keys/Tricolour Leds (“Function Key” Menu); Connections For External Loopback Mode - GE MiCOM P40 Agile Technical Manual

Application Notes
MiCOM P40 Agile P442, P444
Figure 98: Connections for external loopback mode
Once the relay is switched into either of the Loopback modes, a test pattern can be entered
in the "Test Pattern" cell which is then transmitted through the software and/or hardware.
Providing all connections are correct and the software is working correctly, the "Loopback
Status" cell will display "OK". An unsuccessful test would be indicated by "FAIL", whereas a
hardware error will be indicated by "UNAVAILABLE". Whilst the relay is in loopback test
mode, the "IM Output Status" cell will only show the "Test Pattern" settings, whilst the "IM
Input Status" cell will indicate that all inputs to the PSL have been forced to zero.
Care should be taken to ensure that once the loopback testing is complete, the "Loopback
Mode" is set to "Disabled" thereby switching the InterMiCOM channel back in to service. With
the loopback mode disabled, the "IM Output Status" cell will show the InterMiCOM messages
being sent from the local relay, whilst the "IM Input Status" cell will show the received
InterMiCOM messages (received from the remote end relay) being used by the PSL.
Once the relay operation has been confirmed using the loopback test facilities, it will be
necessary to ensure that the communications between the two relays in the scheme are
reliable. To facilitate this, a list of channel statistics and diagnostics are available in the
InterMiCOM COMMS column – see section 10.2. It is possible to hide the channel
diagnostics and statistics from view by setting the "Ch Statistics" and/or "Ch Diagnostics"
cells to "Invisible". All channel statistics are reset when the relay is powered up, or by user
selection using the "Reset Statistics" cell.
Another indication of the amount of noise on the channel is provided by the communications
failure alarm. Within a fixed 1.6 second time period the relay calculates the percentage of
invalid messages received compared to the total number of messages that should have
been received based upon the "Baud Rate" setting. If this percentage falls below the
threshold set in the "IM Msg Alarm Lvl" cell, a "Message Fail" alarm will be raised.
5.7 Programmable function keys and tricolour LEDs ("Function key" menu)
The relay has 10 function keys for integral scheme or operator control functionality such as
circuit breaker control, auto-reclose control etc. via PSL. Each function key has an
associated programmable tri-colour LED that can be programmed to give the desired
indication on function key activation.
These function keys can be used to trigger any function that they are connected to as part of
the PSL. The function key commands can be found in the 'Function Keys' menu. In the 'Fn.
Key Status' menu cell there is a 10 bit word which represent the 10 function key commands
and their status can be read from this 10 bit word. In the programmable scheme logic editor
10 function key signals, DDB 676 – 685, which can be set to a logic 1 or On state are
available to perform control functions defined by the user.
The "Function Keys" column has 'Fn. Key n Mode' cell which allows the user to configure the
function key as either 'Toggled' or 'Normal'. In the 'Toggle' mode the function key DDB signal
output will remain in the set state until a reset command is given, by activating the function
key on the next key press. In the 'Normal' mode, the function key DDB signal will remain
energized for as long as the function key is pressed and will then reset automatically.
A minimum pulse duration can be programmed for a function key by adding a minimum
pulse timer to the function key DDB output signal. The "Fn. Key n Status" cell is used to
enable/unlock or disable the function key signals in PSL. The 'Lock' setting has been
P44x/EN AP/Hb6
(AP) 5-135