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EPS Stromversorgung GmbH
Alter Postweg 101 • 86159 Augsburg
Germany
Fon: +49 821 / 570451-0
Fax: +49 821 / 570451-25
www.eps-germany.de
PSB 9000 3U Slave Series
3.8.1.7 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 situations the following regulations have
been defined:
•
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 power stages and human interaction is required
•
If one or more slave units are cut from AC supply (power switch, blackout, supply undervoltage) while the master
is still running and they come back later, they’re not automatically initialised and included again in the MS system.
Then the initialisation has to be repeated.
•
If the DC terminal of the master unit is switched off due to a defect or overheating, then the total master-slave
system cannot provide power and the DC terminals of all slaves are automatically switched off, too
•
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.
•
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 OV etc. following applies:
•
Any alarm of a slave is indicated on the slave’s HMI 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’ HMI or via digital interface during remote control or remote supervision.
•
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 OC alarm though the global OC limit of the MS system
was not reached. The same can occur with the OP alarm.
3.8.1.8 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.
3.8.2 Series connection
The device from series PSB 9000 3U Slave are supposed to run in master-slave parallel operation. In case differ
-
ent kinds of operation are intended for a device and it is removed from the master-slave system, series connection
of two or multiple units is possible, but with restrictions. For reasons of safety and keeping the insulation intact,
following restrictions apply:
•
Both, negative (DC-) and positive (DC+) DC terminal poles, are connected to PE via type X
capacitors. Thus none of DC minus poles of units in series connection must have a potential
against ground (PE) higher than specified in the technical specifications! The maximum al
-
lowed potential shift varies from model to model and is different for DC plus and DC minus
•
The Share Bus must not be wired and used!
•
Remote sensing must not be wired and used!
•
Series connection is only allowed with models of same kind, i.e. power supply with power
supply, and rating, but at least same current rating like for example PSB 9080-360 3U Slave
with PSB 9080-360 3U or PSB 9080-360 3U Slave
Series connection in master-slave mode is not supported. It means, all units have to controlled separately regarding
set values and DC terminal status, which is only possible in remote control via one of the USB ports.
Due to the max. allowed potential shift on the DC terminal certain models are not allowed for series connection
at all, like the 1500 V model, because the DC plus there is only isolated up to 1800 V. On the contrary, two 500 V
models are eligible for series connection.
