User Manual

Page 56
PS 9000 2U Series
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3.8.1.5 Alarms and other problem situations
Parallel operation, due to the connection of multiple units and their interaction, can cause additional problem situ-
ations which do not occur when operating individual units. For such occurrences the following regulations have
beendened:
• If one or more slave units are switched off on the AC side (power switch, supply undervoltage) and come back
later, they’re automatically included again in the system. The remaining units will continue to work without inter-
ruption, but the entire system will provide less power
• If the DC output of the master unit is switched off due to a defect or overheating, then the total parallel system
can provide no output power
• IfaccidentallymultipleornounitsaredenedasmastertheShareBusparallelsystemcannotbeinitialised
In situations where one or multiple units generate a device alarm like OV, PF or OT following applies:
• Any alarm of a slave is indicated on the slave’s display only
3.8.2 Series connection
Series connection of two or multiple devices is basically possible. But for reasons of safety and isolation, some
restrictions apply:
• Both, negative (DC-) and positive (DC+) output poles, are coupled to PE via type X capacitors
• None DC minus pole of any in the series connection must have a potential of >400 V against
ground (PE)!
• The Share Bus must not be wired and used!
• Remote sensing must not be used!
• Series connection is only allowed with devices of the same kind and model, i.e. power supply with
power supply, like for example PS/PSI 9080-120 2U with PSI 9080-120 2U or PS 9080-120 2U
Series connection is not supported by the software and hardware of the device. It means, all units have to controlled
separately regarding set values and DC output status, whether it is manual control or digital remote control. In
remote control, an almost synchronous control can be achieved by using the Ethernet ports and sending message
as broadcast, so they address multiple units at once.
Thegurebelowdepictstheexemplaryseriesconnectionofthreeidenticaldeviceswith200Vnominaloutput
voltage and the maximum potential shift of any DC- output against PE: