Function and Features 
  Copyright © Itech Electronics Co., Ltd.  32 
range and Auto range. When High range is chosen, press the    (Shift) and 
  (High/Auto) together to switch to Auto range. The indicator “Auto” on 
the VFD will be on. 
  Note
 
There is a temporary OFF to the AC source during the switchover of range. 
3.12 Key lock 
The front panel keys can be locked to prevent unwanted changes to output 
settings and AC source configurations.Follow the steps below to enable/disable 
key lock. 
Press ( (Shift)+  (Lock)button to set the key lock state.If keyboard 
has been locked,the indicator light ”Lock” will display on the VFD .In 
addition,when keyboard are locked,all buttons can’t be used except ON/OFF 
key Shift key and Select key . Press (Shift)+    (Lock)  once again 
will relieve key lock function. 
 
 
 
 
3.13 BNC 
There is a composite terminal at the rear panel of the AC source(see 
description of rear panel), which can be used as: 
Serve  as input signal by external trigger. Connect the 
positive and negative end of the terminal to generate a 
as the control signal for On/Off. When the positive 
and negative end of the terminal is in short circuit, the 
status of AC source is ON. 
Note: Only when the front panel and BNC are set to On at 
the same time, the power supply outputs. Otherwise, the