Elektro-Automatik PS 9000 1U Betriebsanleitung Seite 105

3.9.4.3 Settings on the devices
The master-slave settings in the MENU of the load device(s) also affect the Share bus. For correct 2QO opera-
tion, all involved load units must be slaves on the Share bus. This is achieved by setting the master-slave mode to
OFF or SLAVE, depending on if there is digital master-slave in use or not. For the one load that is master (setting:
MASTER) in the master-slave system the additional parameter "PSI/ELR system" resp. "PSI/EL system" has to
be activated.
On any of the power supplies, you need set parameter "Share bus mode" to MASTER. Also see 3.4.3.1.
For safety of the connected E.U.T / D.U.T and to prevent damage, we recommend to adjust supervision thresholds
like OVP, OCP or OPP on all units to the desired levels, which will then switch off the DC output resp. the DC input
in case of excess.
3.9.4.4 Restrictions
After all electronic load slaves have been connected to the Share bus with one power supply as master, they can-
not limit their input voltage anymore to what you adjust as "U set" on the device. The correct voltage level comes
from the master unit and has to be adjusted there.
3.9.4.5 Application example
Charging and discharging a battery with 24 V/100 Ah, using configuration A from above.
• Power supply PS 9080-100 1U with: I
• Electronic load EL 9080-170 B set to: I
probably UVD = 20 V with event type "Alarm" to stop discharging at a certain low voltage threshold
• Assumption: battery has a voltage of 26 V at test start
• DC input(s) and DC output(s) of all units switched off
In this combination of devices it is recommended to always switch on the DC output of the
source first and then the DC input of the sink.
1. Discharge of the battery to 24 V
Setup: Voltage on the power supply set to 24 V, DC output of power supply and DC input of load activated
Reaction: the e-load will discharge the battery with a maximum current of 50 A in order to discharge it to 24 V. The
power supply delivers no current at this moment, because the battery voltage is still higher than what is adjusted on
the power supply. The load will gradually reduce the input current in order to maintain the battery voltage at 24 V.
Once the battery voltage has reached 24 V with a discharge current of approx. 0 A, the voltage will be maintained
at this level by charging from the power supply.
The power supply determines the voltage setting of the load via the Share bus. In order to avoid
deep discharge of the battery due to accidentally setting the voltage on the power to a very low
value, it is recommended to configure the undervoltage detection feature (UVD) of the load, so
it will switch off the DC input when reaching minimum allowed discharge voltage. The settings
of the load, as given via the Share bus, can't be read from the load's display.
2. Charging the battery to 27 V
Setup: Voltage on the power supply set to 27 V
Reaction: the power supply will charge the battery with a maximum current of 10 A, which will gradually reduce
with increasing voltage as a reaction to the changing internal resistance of the battery. The load absorbs no current
at this charging phase, because it is controlled via the Share bus and set to a certain voltage, which is still higher
than the actual battery voltage and the actual output voltage of the power supply. When reaching 27 V, the power
supply will deliver only the current needed to maintain the battery voltage.
EA Elektro-Automatik GmbH
Helmholtzstr. 31-33 • 41747 Viersen
Germany
= 10 A (charging current, 1/10 of rated capacity), P
Set
= max. discharging current of the battery (eg. 50 A), P
Set
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
PS 9000 1U Series
Set
www.elektroautomatik.de
ea1974@elektroautomatik.de
= 3000 W
= 2400 W, plus
Set
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