User Manual

Page 91
EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
[e-mail]
PSB 9000 2.5 kW Series
• 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.
• 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o󰀨,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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o󰀨itsDCterminal.Theslaveswillfallbacktosingleoperationmode,
butalsoswitcho󰀨theirDCterminal.TheMSPalarmcanbedeletedbyinitialising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 initialised 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 automati-
callyinitialisetheMSsystemagain,ndingandintegratingallactiveslaves.Inthiscase,MScanberestored
automatically.
• Ifmultiple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 partic-
ular 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.
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
o, 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.
• Slave devices with a display have an extra option in the conguration page for master-slave
which can be activated to switch o the back light of the display after some time. This can
be helpful, because after initialization of the MS system the slaves’ displays are not needed
anymore. The feature itself is, however, identical to the option in the HMI settings.
3.12.2 Series connection
Besides being able to work as a power supply, the device is also an electronic load.
Series connection isn’t a permissible operating method for electronic loads and must not be
installed or operated under any circumstances!
Explanation of this restriction:
Series operation of electronic load absolutely requires a balanced voltage distribution over all includes units, so
no unit has to “see” an overvoltage. This can only be achieved by additional controller hardware which balances
the devices. Such a feature is not included and also not available as option.
Unbalanced voltage and thus possible overvoltage can occur anytime when the units regulate their internal resis-
tancewhilebeingslightlydi󰀨erentintheirreactiontime.ThisespeciallyisthecasewhenswitchingtheDCinputs
of the units on at almost the same time, after which the internal regulators don’t start to drive the load’s resistance
from high down to low all in the same moment.
Additionally, for protection of the units against overvoltage and subsequent damage, it would require to install a
voltage supervision hardware on every unit, plus a mechanism that could immediately cut the external voltage,
such as a contactor.