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PSI 9000 2U Series
EA Elektro-Automatik GmbH
Helmholtzstr. 31-33 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
3.9.1.4 Operating the master-slave system
After successful configuration and initialisation of the master and slave units, these will show their status in the
displays. While the master merely shows “Master” in the status area, the slave(s) will continuously show like this,
as long they are in remote control by the master:
The slaves can no longer be controlled manually or remotely, neither via the analog nor via digital interfaces. They
can, if needed, be monitored by reading actual values and status.
The display on the master unit changes after initialisation and all set values are reset. The master now displays
the set and actual values of the total system. Depending on the number of units, the total current and power will
multiply. The following applies:
•
The master can be treated as a standalone unit
•
The master shares the set values across the slaves and controls them
•
The master is remotely controllable via the analog or digital interfaces
•
All settings for the set values U,I and P (monitoring, settings limits etc.) will be adapted to the new total values
•
All initialised slave will reset any limits (Umin, Imax etc.), supervision thresholds (OVP, OPP etc.) and event set-
tings (UCD, OVD etc.) to default values, so these don’t interfere the control by the master
In order to easily restore all these settings after leaving MS operation, it is recommended to
make use of the user profiles (see „3.7. Loading and saving a user profile“
•
If one or more slaves report an device alarm, this will be displayed on the master and must be acknowledged
there so that the slave(s) can continue operation. If the alarm had caused the DC output to be switched off then
this will be reinstated automatically by the master unit once the alarm has been acknowledged
3.9.1.5 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:
•
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 output and human interaction is required.
•
If one or more slave units are switched off on the AC side (power switch, 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 DC output of the master unit is switched off due to a defect or overheating, then the total master-slave
system can provide no output power and the DC outputs of all slaves are automatically switched off, too.
•
If the master unit is switched off on the AC side (power switch, supply undervoltage) and comes back later, it
will automatically 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, PF or OT 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 particu-
lar alarms can be read from the slave units displays. This also applies for remote control or remote supervision,
because the master can only report the most recent alarm.
