Manual

© EA Elektro-Automatik in 2022, this information is subject to change without notice 8533200840_manual_elr_10000_2u_3kw_en_02
3.11.1.7 Operating the master-slave system
After successful conguration and initialization of the master and slave units, they will show their status in the in the status
area of their displays. The master would show MS mode: Master while the slave(s) would show MS mode: Slave plus Remote:
Master-slave, as long they are in remote control by the master.
From now on the slaves can no longer be controlled manually or remotely, neither via the analog nor via digital interfaces.
They can, if needed, be monitored via these interfaces by reading actual values and status.
The display on the master unit will recongure after initialization and all set values are reset. The master now displays the set
and actual values of the total system. Depending on the number of units, the adjustable current and power range will multiply,
while the resistance range will decrease. Then following applies:
• The system, represented by the master, can be treated like a standalone unit
• The master shares the set values etc. across the slaves and controls them
• The master is remotely controllable via the analog or digital interfaces
• All settings for the set values U,I, P and R on the master, plus also all related values from supervision, limits etc. should be
adapted to the new total values
• All initialized slaves will reset any limits (U
Min
, I
Max
etc.), supervision thresholds (OVP, OPP etc.) and event settings (UCD, OVD
etc.) to default values, so these don’t interfere the control by the master. As soon as these values are modied on the master,
they are transferred 1:1 to the slaves. Later, during operation, it might occur that a slave causes an alarm or an event earlier
than the master, due to imbalanced current or slightly faster reaction.
In order to easily restore all these settings to what was congured before activating MS operation, it’s
recommended to make use of the user proles (see “3.9. Loading and saving user proles”)
• If one or more slaves report a device alarm, it will be signaled on the master and must be acknowledged also there. so that
the slave(s) can continue their operation. Since an alarm causes the DC inputs to be switched off and can only reinstate
the on/off condition automatically after PF or OT alarms, where the reaction to the alarms is congurable, action from an
operator or a remote control software may become necessary.
• Loss of connection to any slave will result in shutdown of all DC inputs as a safety measure and the master will report this
situation in the display with a pop-up telling “Master-slave security mode”. Then the MS system has to be re-initialized, either
with or without prior re-establishment of the connection to the disconnected unit(s).
• All units, even the slaves, can be externally shut down on their DC inputs using the pin REM-SB of the analog interface. This can
be used as some kind of “emergency off”, here usually a contact (maker or breaker) is wired to this pin on all units in parallel.
3.11.1.8 Alarms and other problem situations
Master-slave operation, due to the connection of multiple units and their interaction, can cause additional problem situations
which do not occur when operating individual units. For such occurrences the following regulations have been dened:
• Generally, if the master loses connection to any slave, it will generate an MSP (master-slave protection) alarm, pop up a
message on the screen and switch off its DC input. The slaves will fall back to single operation mode and also switch off
their DC input. The MSP alarm can be deleted by initializing the master-slave system again. This can be done either in the
MSP alarm pop-up screen or in the MENU of the master or via remote control. Alternatively, the alarm is also cleared by
deactivating master-slave on the master unit
• If one or more slave units are cut from AC supply (power switch, blackout, supply undervoltage) and come back later, they’re
not automatically initialized and included again in the MS system. Then the init has to be repeated.
• If the master unit is cut from AC supply (power switch, blackout) and comes back later, the unit will automatically initialize
the MS system again, nding and integrating all active slaves. In this case, MS can be restored automatically.
• If accidentally multiple or no units are dened as master the master-slave system can’t be initialized
In situations where one or multiple units generate a device alarm like OVP etc. following applies:
• Any alarm of a slave is indicated on the slave’s display and on the master’s display
• If multiple alarms happen simultaneously, the master only indicates the most recent one. In this case, the particular alarms
can be read from the slave units displays or via digital interface by any software.
• All units in the MS system supervise their own values regarding overvoltage, overcurrent and overpower and in case of
alarm they report the alarm to the master. In situations where the current is probably not balanced between the units, it can
occur that one unit generates an OCP alarm though the global OCP limit of the MS system was not reached. The same can
occur with the OPP alarm.