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EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
PSB 9000 3U Series
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Loss of connection to any slave will result in shutdown of all DC terminals, as a safety measure, and the master
will report this situation in the display with a pop-up “Master-slave security mode”. Then the MS system has to
be re-initialised, either with or without re-establishing connection to the disconnected unit(s) before.
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All units, even the slaves, can be externally shut down on the DC terminals using the pin REM-SB of the analog
interface. This can be used as some kind of emergency off, where usually a contact (maker or breaker) is wired
to this pin on all units in parallel.
3.12.1.6 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 defined:
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If the DC part of one or more slave units is switched off due to defect, overheating etc., the whole MS system
shuts down the DC terminal and human interaction is required
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If one or more slave units are cut from AC supply (power switch, blackout, supply undervoltage) and come back
later, they’re not automatically initialised and included again in the MS system. Then the init has to be repeated.
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If the DC terminal of the master unit is switched off due to a defect or overheating, then the total master-slave
system cannot sink/provide power anymore and the DC terminals of all slaves are automatically switched off, too
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If the master unit is cut from AC supply (power switch, blackout) and comes back later, the unit will automati-
cally initialise the MS system again, finding and integrating all active slaves. In this case, MS can be restored
automatically.
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If accidently multiple or no units are defined as master the master-slave system cannot be initialised
In situations where one or multiple units generate a device alarm like OVP etc. following applies:
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Any alarm of a slave is indicated on the slave’s display and on the master’s display
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If multiple alarms happen simultaneously, the master only indicates the most recent one. In this case, the par-
ticular alarms can be read from the slave units displays or via digital interface by any software.
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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.
3.12.1.7 Important to know
In case one or several units of a parallel system are not going to be used and remain switched
off, depending on the number of active units and the dynamics of the operation it may become
necessary to disconnect the inactive units from the Share bus, because even when not powered
the units can have a negative impact on the Share bus due to their impedance.
3.12.2 Series connection
Besides being able to work as a power supply, the device is also an electronic load.
Series connection is not a permissible operating method for electronic loads and must not be
installed or operated under any circumstances!
3.12.3 Operation as battery charger (source mode)
A power supply (here: PSB 9000 in source mode) can be used as a battery charger, but with some restrictions,
because it misses a battery supervision and a physical separation from the load in form of a relay or contactor,
which is sometimes featured with real battery chargers as a protection.
Following has to be considered:
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No false polarity protection inside! Connecting a battery with false polarity will damage the power supply severely,
even if it is not powered.
