Protection functions – HMC Electronics MDL Series BK Precision DC Electronic Load System Module User Manual
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Protection Functions
The electronic load has the following protection functions: Overvoltage protection (OVP),
overcurrent protection (OCP), overpower protection (OPP), overtemperature protection (OTP), and
local and remote reverse voltage protection (LRV/RRV).
The mainframe will act appropriately once any of the above protections are active. You can press
any button on the front panel to restore the protection function. For example, if the electronic
load triggers the overtemperature protection, the buzzer will alarm, the input will automatically
turn off, and the mainframe VFD will display OTP.
Overvoltage Protection (OVP)
If the OVP circuit has triggered, input will turn off, buzzer alarm will go off, and the status register’s
OV and VF bit will be set. The mainframe will display OVP and the condition will remain until they
are reset. Once overvoltage protection occurs, the 8-pin connector’s VF pin on the rear panel will
output TTL high voltage level. You can control the output state of the power supply under test via
this pin (see Figure 31).
Operations to Clear the OVP State
Check whether the input voltage is within the electronic load’s rated voltage or the programmed
protection voltage ranges. If it is outside the range, please disconnect the device under test. Then
press any key on the front panel or remotely send SCPI command PROTection:CLEar. The OVP
displayed on the front panel will turn off and the electronic load exits OVP protection state.
Overcurrent Protection (OCP)
The electronic load includes both hardware and software overcurrent protection features.
Hardware OCP - The electronic load’s maximum input current will be limited to approximately
110% of the current range. Once the hardware OCP is triggered, the status register’s OC bit will be
set. When the hardware OCP is removed, the status register’s OC bit will be reset. Hardware
overcurrent protection will not affect the electronic load’s on/off state.
Software OCP - Users can set the electronic load’s software OCP value with the following steps.
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