Protection Functions; Over Voltage Protection (Ovp); Over Current Protection (Ocp); Over Power Protection (Opp) - ITech IT8700 Series User Manual

4.11 Protection functions

Load has the following protection functions: over voltage protection （OVP） ,over
current protection（OCP）, over power protection(OPP), over temperature
protection(OTP), reverse voltage protection(LRV/RRV）.
The mainframe will act appropriately once any of the above protection is active.
You can press any button on front panel to restore the protection function. For
example, the electronic load come into over temperature protection, the buzzer
will alarm, the input will automatically shut down and Main frame VFD will
display OTP.

4.11.1 Over voltage protection (OVP)

If the OVP circuit has triggered, buzzer alarm, the main frame screen will
displays (OVP), the condition will remain until they are reset.
Operations to clear the OVP state:
Check whether the input voltage is in the load's rated voltage or the
programmed protecting voltage ranges. If it is outside of the range, please
disconnect the instrument under test. Press any key on the front panel (or send
commandPROTection:CLEar), the (OVP) displayed on the front panel will
disappear, load exits OVP protection state.

4.11.2 Over current protection (OCP)

The electronic load includes both hardware and software over current
protection features.
 Hardware OVP: load's maximum input current will be limited at about 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 over current protection
won't affect load's on/off state.
 Software OCP: users can set load's software OCP value, steps:
time before alarm. When the software OCP function is active, if the load
current value is over the over current protection set value, load will
automatically off, VFD displays OCP. At the same time, the OC and PS bits
in the status register will be set and they will remain until they are reset.
Operations to clear the OCP state:
Check whether the input current is within the load's rated current or the
programmed protecting current ranges, if it is outside the range, please
disconnect the instrument under test. Press any key on the front panel (or send
commandPROTection:CLEar), the (OVP) displayed on the front panel will
disappear, load exits OCP protection state.

4.11.3 Over power protection (OPP)

The electronic load includes both hardware and software OPP features.

Hardware OPP: the electronic load allows user to set a power protection
limit in hardware which will limit the power in the range you set when the
OPP condition occur. Hardware OPP will not change the load ON/OFF
state.
 Software OPP: users can set load's software OPP value, steps:
Shift+5>Protect>Point set OPP power value, Plimit set alarm delay. If the
load power value is OPP delay time, load will automatically turned off, VFD
will display OPP. At the same time, the OP and PS bits in the status register
5 5
>Protect>Alimit set ON, Apoint set OCP current value, Adelay set delay
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