Ametek Amrel PLA Series Operation Manual page 21

Oscillation Protection (OSC):
The eLoad offers oscillation protection to prevent the system or DUT from being damaged during unstable operating
conditions. If the oscillation exceeds 1.2% of rated voltage or rated current depending on user's operational mode and
over 1.5Khz frequency threshold for longer than the programmed oscillation delay, the input will shut down and an alarm
message "OSC" will display. For applications with load input having dc plus ac perturbations, the OSC protection can be
disabled. Please refer to the menu tree for further disabling procedures.
CAUTION
Product used with oscillation protection turned off may cause product failure. Failure occurring as a result of
oscillation application or turn-off of this feature will not be covered under warranty.
Anti-Oscillation:
In addition to the "OSC" protection, the eLOAD has four selectable system bandwidth controls: Default, OSC1, OSC2
and OSC3, that will adjust the system speed to resolve potential oscillation problem s. The slew time ranges will vary
according to the range selected. At Default state, it has the widest bandwidth and fast transient time to achieve -3db
frequency at 10Khz . At OSC1 state, it has the normal bandwidth and transient time. At OSC2 and OSC3 state, th ey have
the slower transient time in order to have the better stability. The selection of different bandwidth ranges allows for
higher speed or slower stable applications.
Self-Test Failure:
The self-test assures early detection of hardware problems and forces the input off when a failure does occur.
The appropriate bit(s) in the status registers are set when any of the above protection features are active. The front panel
display will indicate which condition(s) have been detected.
Resetting Latched Protection
All of the protection features remain latched (set) when they are tripped. The latched protection features can be reset via
the front panel PROT (CLEAR) key or the digital interfaces. The condition that caused the protection feature to trip must
be removed or it will trip again as soon as it is reset.
Bias Voltage Protection (VPP & VNP)
For the electronic load to operate properly it requires a n internal +12 V and -12V voltage to bias different parts of the
DC DC
system. In the case that the +12V bias voltage malfunctions, a "VPP" error message will appear indicating a voltage
positive power error. If the -12V bias voltage malfunctions, a "VNP" error will appear indicating a voltage negative
power error. For either of these error messages, please contact AMETEK Technical Support. The electronic load most
likely had a serious internal malfunction that caused the system to shutdown.
Note: For VPP and VNP failures, please refrain from repairing the unit, for it may inflict further damage.
In Fault Protection (INF)
If the electronic load is forced to sustain too much power, current or voltage in a short amount of time, the internal power
stage may have been damaged. If the damage is serious enough, the system hardware will shut down and the display will
show an "In_Fault" or "INF" error message. When this message occurs, please contact AMETEK customer service. The
electronic load most likely has a power stage malfunction and will no longer operate normally.
Note: For INF failure, please refrain from repairing the unit, for it may inflict further damage.
M470039-01 REV-F Page 20