Basic Operations 
  Copyright © ITECH Electronic Co., Ltd.  31 
command “PROTection:CLEar”). Then OCP on the load screen will disappear, 
and the load will exit the OCP status. 
Overpower protection (OPP) 
The electronic load has two kinds of overpower protection: hardware overpower 
protection and software overpower protection. 
Hardware  overpower  protection:  the  user  can  set  the  hardware  overpower 
protection value, and the load power will be limited at the present power by the 
hardware.  The  present  ON/OFF  status  of  the  load  cannot  be  changed  in 
hardware overpower protection. 
Software  overpower  protection:  the  user  can  set  the  software  overpower 
protection value of the load. 
Clearing overpower protection: 
Check whether the power of the test object is within the rated power range of 
the load or within the protection power setting range. If the power of the test 
object  is  beyond  the  rated  power  range  or  protection  power  setting  range, 
disconnect the test object, and press any key on the front panel (or send the 
command “PROTection:CLEar”). Then OPP on the load screen will disappear, 
and the load will exit the OPP status. 
Over-temperature protection (OTP) 
When the temperature of the power component in the load exceeds 85℃, the 
temperature  protection  will  be  enabled.  In  this  case,  the  load  will  be 
automatically OFF, and the LCD will display OTP. At the same time, the OT and 
PS position in the status register will be set and kept until the load is reset. 
Clearing over-temperature protection: 
When the load temperature decreases to the protection temperature, press any 
key on the front panel (or send the command “PROTection:CLEar”). Then OTP 
on the load screen will disappear, and the load will exit the OTP status. 
Out-of-range frequency protection 
When the measured frequency is beyond the frequency range (45HZ to 450HZ), 
“FREQ ERR” will be displayed. 
Undervoltage protection 
When  the  load  is  applied  and  current  is  sinking,  the  voltage  will  decrease 
instantly as a result of impedance of the test unit. When the voltage is lower 
than the required input voltage, loading will be stopped to protect the load and 
test  unit,  and  the  UV  prompt  will  appear  on  the  interface.  The  user  should 
decrease the loading current or CF value to ensure normal operation. 
Loading failure 
Loading failure occurs in the following cases: 
⚫  The input voltage is 0 during loading; 
⚫  The voltage is reduced to 0 during loading; 
⚫  The load hardware is abnormal; 
⚫  The voltage and loading current fluctuates continuously. 
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