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EPS Stromversorgung GmbH
Alter Postweg 101 • 86159 Augsburg
Germany
PSI 9000 3U Series
Fon: +49 821 / 570451-0
Fax: +49 821 / 570451-25
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 high (mains overvoltage)
•
AC input voltage too low (mains undervoltage, mains failure)
•
Defect in the input circuit (PFC)
•
Not all required AC input phases are connected (see
„2.3.4. Connection to AC supply“
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.
3.3.2 Overtemperature
An overtemperature alarm (OT) can occur if an excess temperature inside the device and causes it to stop supplying
power temporarily. 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.
An OT alarm has a lower priority than an OV alarm (overvoltage). If an OV alarm occurs during
an OT alarm, then the message “OT” will be overwritten by “OV”
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 limit (OVP, 0...110% U
Nom
) or the connected load somehow returns voltage higher than set for the overvolt
-
age alarm limit
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 reaches 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 reaches 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.
