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EPS Stromversorgung GmbH
Alter Postweg 101 • 86159 Augsburg
Germany
Fon: +49 821 / 570451-0
Fax: +49 821 / 570451-25
www.eps-germany.de
PSI 9000 2U Series
3.3
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 „3.6. Alarms and monitoring“.
As a basic principle, all alarm conditions are signalled optically (text + message in the display), acoustically (if
activated) and as a readable status and alarm counter via the digital interface. In addition, the alarms OT and
OVP are reported as signals on the analogue interface. For later acquisition, an alarm counter can be read from
the display or via digital interface.
3.3.1
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)
As soon as a power fail occurs, the device will stop to supply power and switch off the DC output. 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 the device is switched off. This can be ignored.
The condition of the DC output after a PF alarm during normal operation can be set up. See
„3.4.3. Configuration via MENU“
.
3.3.2
Overtemperature
An overtemperature alarm (OT) can occur from an excess temperature inside the device and temporarily causes
it to stop supplying power. After cooling down, the device will automatically continue to supply power, while the
condition of the DC output remains and the alarm doesn’t require to be acknowledged.
3.3.3
Overvoltage protection
An overvoltage alarm (OVP) will switch off the DC output and can occur if:
•
the power supply itself, as a voltage source, generates an output voltage higher than set for the overvoltage
alarm threshold (OVP, 0...110% U
Nom
) or the connected load somehow returns voltage higher than set for the
overvoltage alarm limit
•
the OV threshold has been adjusted too close above the output voltage. If the device is in CC mode and if it
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 of the power supply acoustically or optically that the device probably has
generated an excessive voltage which could damage the connected load application.
•
The device is not fitted with protection from external overvoltage
• The changeover from operation modes CC -> CV can generate voltage overshoots
3.3.4
Overcurrent protection
An overcurrent alarm (OCP) will switch off the DC output and can occur if:
•
the output current in the DC output exceeds the adjusted OCP limit.
This function serves to protect the connected load application so that this is not overloaded and possibly damaged
due to an excessive current.
3.3.5
Overpower protection
An overpower alarm (OPP) will switch off the DC output and can occur if:
•
the product of the output voltage and output current in the DC output exceeds the adjusted OPP limit.
This function serves to protect the connected load application so that this is not overloaded and possibly damaged
due to an excessive power consumption.
