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MDE/A133 2295 001
MX3EG1A
3.5.3 DB dead-bar mode ON-CHECK
The device checks that the generator frequency and voltage lie
within the limits defined by Dfb and DUb: if these do not lie within
the mentioned limits, the device carries out all the adjusting
operations necessary to make them lie within the range of values
defined. The 'parallel breaker closing' command will be then sent.
3.6 Main and spare settings
The device can store two groups of settings, namely 'main' and
spare', which can be selected through keyboard, PC or network.
The group of setting being used is shown on the display as
'SETTINGS IN USE'.
Independently of the selection made, the device can be 'forced'
to use the SPARE settings. This 'forcing' can be carried out from
the network or by permanently enabling the digital input (IN DIG 1)
configured to such aim. This condition is signalled by the
characters <!> which appear near the group already selected;
when the input is disabled, the group of settings previously
selected is restored and the characters <!> disappear (see
paragraph 6.1.3).
4. ADDITIONAL FUNCTIONS
4.1 Diagnostics
Diagnostic activities are envisaged which are automatically carried
out upon powering on the device as well as from time to time
during the running, and which allow the following actions to be
performed:
- signalling fault or failure conditions. This signal de-energizes
the diagnostic relay, turns off the green LED (running device)
and turns on the red LED ( faulty device);
- locking out the device in the event of faults that might entail ill-
timed operation (VITAL FAULTS)
- displaying the code referring to the type of fault occurred.
The following faults are defined as NOT VITAL FAULTS:
- output relay (X1 - X5) faulty
- communication faulty
- internal clock faulty
The following faults are defined as VITAL FAULTS:
- feeder faulty
- EEPROM faulty
- internal or exteranl RAM faulty
- analog/digital converter faulty
In the event of vital faults the device automatically displays the
code relative to the kind of fault occurred; if allowed by the device,
this condition can only be solved by enabling the 'settings change'
command.
In the event that, upon starting up the equipment, an EEPROM
failure makes it impossible to retrieve the information on the
selected dialogue language, the device will continue on working
using Italian as default language.
The device includes the 'Watch Dog'.
The diagnostic activity is also aimed at signalling any condition of
'inhibited equipment': the relevant code is displayed, the diagnostic
relay is de-energized and the red LED (faulty device) lights on.
This condition can only be solved by enabling the 'settings
change' command.
The diagnostic menu also indicates the date when last changes
were made to the equipment.
4.2 Output circuits
The output circuits are composed of six relays: each of them is
provided with two contacts (see block diagram).
The X6 relay, normally energized, is strictly assigned to the
diagnostic function.
Each remaining relay, if duly programmed from the keyboard, PC
or network, can be set to carry out one or more functions.
The operation of these six relays is of monostable type: that is,
it allows to immediate return to the quiescent position when the
cause that operated it is removed.
The output relays, except for the diagnostic relays, can all be
simultaneously set to 'normally energized' (NORMAL.ON=ON)
or to 'normally de-energized' (NORMAL.ON=OFF): the selection
occurs bymeans of the S1 jumper which is accessible when the
relay has been pulled out (see fig. 2a, 2b).
