Protection Features - Ametek Amrel PLA Series Operation Manual

Protection Features:

The electronic load includes the following protection features:
Over Voltage (OV):
The eLOAD has an Over Voltage Protection (OV) set at 105% of the full voltage rating. If the input voltage exceeds
105% of the over voltage threshold, the input will shut off and an alarm message "OV" will display.
Over Current (OC):
The eLOAD has an Over Current Protection (OC) set at 110% of the full current rating. If the input current exceeds
110% of the over current threshold, the input will shut off and an alarm message "OC" will display.
Overpower (OP):
The eLOAD has an Overpower Protection function set at 105% of rated power. If the power based on DC input terminals
voltage and current exceeds 105% of rated power, the unit will display warning message "OP" and the load will limit
input current level to maintain the input power to prevent unit from over overload. Over temperature protection may trip
if the input power exceeds the rated power persistently.
For eLOAD (with firmware version 2.86 or earlier), has an Overpower Protection function set at 105% (PLW Models)
and 110% (PLA Models) of full Power Rating. If the accumulated energy based on operating voltage and current exceeds
the overpower threshold, the input will shut down and display the alarm message "OP".
Over Temperature (OTP):
The electronic load has a n over temperature protection circuit, which will turn off the input if the internal temperature
exceeds safe limits. Over-temperature is usually the worse condition to happen to an electronic load due its highly
destructive effects. During high temperature operation (OTP condition), all internal MOSFETS are working near their
full capacity a nd can fail due to excessive heat. To prevent over temperature, the electronic load has a built in redundant
over temperature protection. In short, the OTP offers both a temperature sensor circuit that controls the internal cooling
system and a hardware thermal switch that shuts down the input when the temperature threshold is exceeded . The
heatsink temperature can be display at front panel with Meter Mode selection or Query via remote command.
Reverse Voltage (RCP):
The electronic load has the internal parallel diodes to short the input in the presence of a reversed DC voltage input. The
front panel display with the alarm message "RCP" will indicate this condition has been detected.
Remote Sense Fault (RSF):
If the connection to the sense leads is not proper when operating under remote sense mode, the input will be forced off
with the alarm message "RSF"; Remote Sense Fault. Two common errors that can result in " RSF" failure are while the
"Measure Sense" is set to remote, the sense leads are not connected or if the leads are connected and the connection is
lost. The latter can become a serious problem in CP mode. In Constant Power mode, the electronic load will maintain the
set wattage by balancing the voltage and current. If the remote sense leads are disconnected, the V of the load will
MON
sense zero voltage and sink the amount of current needed to keep the same power level until OC or other protection are
triggered. The "RSF" protection will trigger if the voltage deviation between the actual measured voltage and remote
sense voltage exceeds a set limit, forcing the input off until the conditions is cleared.
Note: "RSF" error signal has precedence over OC with remote sense enabled, and will trigger if connection is lost.
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