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EA Elektro-Automatik GmbH
Helmholtzstr. 31-37 • 41747 Viersen
Germany
Fon: +49 2162 / 3785-0
Fax: +49 2162 / 16230
www.elektroautomatik.de
PSB 9000 3U Series
3.4
Alarm conditions
This section only gives an overview about device alarms. What to do in case your device indi-
cates an alarm condition is described in section „3.7. Alarms and monitoring“.
As a basic principle, all alarm conditions are signalled optically (text + message in the display) and acoustically
(if activated), as well as status via digital interface. In addition, the alarms are reported as signals on the analog
interface. For later acquisition, an alarm counter can also be shown on display or read via digital interface.
3.4.1
Power Fail
Power Fail (PF) indicates an alarm condition which may have various causes:
•
AC input voltage too low (mains undervoltage, mains failure)
•
Defect in the input circuit (PFC)
•
One or multiple power stages in the device are faulty
As soon as a power fail occurs, the device will stop to supply or sink power and switch off the DC terminal. In case
the power fail was an undervoltage and is gone later on, the alarm will vanish from display and doesn’t require to
be acknowledged.
Switching off the device by the mains switch can’t be distinguished from a mains blackout and
thus the device will signalise a PF alarm every time it is switched off. This can be ignored.
The condition of the DC terminal after a PF alarm during normal operation can be set up. See
„3.5.3. Configuration via MENU“
.
3.4.2
Overtemperature
An overtemperature alarm (OT) can occur from an excess temperature inside the device and temporarily causes
it to switch of the power stage(s). This can occur if the ambient temperature exceeds the maximum ambient tem-
perature rating for the device. After cooling down, the device will automatically switch the power stage back on
and the alarm doesn’t require to be acknowledged.
3.4.3
Overvoltage protection
An overvoltage alarm (OVP) will switch off the DC power stage and can occur if:
•
the device itself, when running in source mode, or an external source (in sink mode) brought a voltage to the
DC terminal higher than set for the overvoltage alarm threshold (OVP, 0...103% U
Nom
) or the connected load
somehow returns voltage higher than this threshold
•
the OVP threshold has been adjusted too close above the output voltage in source mode and if the device is in
CC regulation mode and then experiences a negative load step, it will make the voltage rise quickly, resulting in
an voltage overshoot for a short moment which can already trigger the OVP
This function serves to warn the user acoustically or optically that the device probably has generated or experienced
an excessive voltage which could damage the connected load application or the device.
•
The device is not fitted with protection from external overvoltage and could even be dam
-
aged when not powered
• The changeover from operation modes CC -> CV in source mode can cause voltage
overshoots
3.4.4
Overcurrent protection
An overcurrent alarm (OCP) will switch off the DC power stage and can occur if:
•
the current in the DC terminal reaches the adjusted OCP limit.
This function serves to protect the connected load application (source mode) or the external source (sink mode)
so it this is not overloaded and possibly damaged due to an excessive current.
3.4.5
Overpower protection
An overpower alarm (OPP) will switch off the DC terminal and can occur if:
•
the product of the voltage and current in the DC terminal reaches the adjusted OPP limit.
This function serves to protect the connected load application (source mode) or the external source (sink mode)
so that this is not overloaded and possibly damaged due to an excessive power.
