Page 82
EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
PSI 9000 15U/24U Series
4.
Other information
4.1
Special characteristics of master-slave operation
The units in the cabinet run in master-slave operation. This can cause additional problem situations which do not
occur when operating units outside of master-slave. For such occurrences the following regulations have been
defined:
•
If the DC part of one or more slave units is switched off due to a defect or overheating etc., the entire cabinet
shuts down the power output and human interaction is required
•
If one or more slave units are cut from AC supply (power switch, blackout, supply undervoltage) and come back
later, they’re usually automatically initialised and included again in the MS system. In situations where the auto
-
matic initialisation fails, it can be repeated manually in the MENU of the master unit.
•
If the DC output of the master unit is switched off due to a defect or overheating, then the cabinet cannot provide
output power anymore
•
If the master unit is cut from AC supply (power switch, blackout) and comes back later, it will automatically ini
-
tialise the MS system again, finding and integrating all active slaves and making it possible to continue running
the cabinet if being supervised by a control software which can handle such events
In situations of device alarms like OV or PF etc. following applies:
•
Alarms can be generated by any slave unit in the cabinet, whereas the slave unit cannot indicate anything and
the master unit only displays the alarm itself, but not which unit actually caused it. This can only be monitored
by software and when reading the alarm status of all units in the cabinet separately, because every unit has its
own alarm counter
•
If multiple alarms happen simultaneously, the master only indicates the most recent alarm in the display, but the
alarm counter collects them all
•
All units in the MS system supervise their own values regarding overvoltage, overcurrent and overpower and
in case of alarm slave units report to the master unit. 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 cabinet
was not reached. The same can occur with the OPP alarm.
