AMETEK PLA-PLW - Manual (Page 18)

30% for CR mode or 0.3% for CP mode, that particular mode will need to be recalibrated. As a factory default,
all loads are calibrated to its optimal condition. Please verify the calibration inaccuracy carefully or contact
$0(7(.33'Technical Support before re-calibrating the unit.
Precautions for Testing Batteries
As a precaution, when testing batteries prevent from operating in CV mode and make sure that the load does
not enter the unregulated state. If a battery is connected to a short circuited load (UNR state), the load will
draw max current and may cause permanent damage to the load, battery under test and possibly start a fire.
Under Voltage Lockout Protection (UVL):
The programmable under voltage lockout feature allows the user to set a trip point between zero and full-scale
voltage (V-On Voltage Threshold). The input will remain off until the input voltage is greater than the pre-
programmed value or the V-On Voltage threshold. For the V-On (UVL) feature, there are two modes that can
be set. In “continuous” mode, the UVL detection will remain active, and each time the voltage drops below the
set threshold voltage, the UVL protection will shut off the input. Under “input on” mode, the UVL detection will
only trigger once to shut down the input and will reset each time the input is cycled. The only way to clear a
UVL protection message is to increase the input voltage beyond the V-On threshold. As a recommended
setting, the V-On threshold should be set equivalent to at least the unit’s min. operating/compliance voltage.
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 the frequency threshold for longer than the programmed
oscillation delay, the input will shutdown and an alarm message “OSC” will display. For applications that are
oscillatory in nature, the OSC protection can be disabled. Please refer to the menu tree for further disabling
procedures.
Anti-Oscillation (system bandwidth control):
In addition to the “OSC” protection, the eLOAD has four selectable bandwidth controls: Default, OSC1, OSC2
and OSC3 (DISABLE to disable OSC protection), that will adjust the system speed to resolve potential
oscillation problems. The slew time ranges will vary according to the range selected. At Default state, it has the
widest bandwidth and fast transient time. At OSC1 state, it has the normal bandwidth and transient time. At
OSC2 and OSC3 state, they 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 eLOAD to operate properly it requires an internal +12 V
DC
and -12V
DC
voltage to bias different parts of
the 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 AMREL Technical Support.
The eLOAD 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.
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