Function and Features 
  Copyright © ITECH Electronic Co., Ltd.  35 
3.20 External Signal Control Interface 
Besides the RS232 communication interface, the rear panel is also equipped 
with a DB-9 COM interface, which is the external signal control interface used in 
auto test. The pin definitions are as follows. 
 
Pins of Plug 
The auto test runs last step. 
The auto test starts to run. 
During the auto test, the input is 
turned on. 
Output the failure signal of the 
auto test. 
The auto test runs next step. 
The auto test outputs via signal. 
The warning tone signal of auto 
test outputs. 
 
You can control the auto test process and test results by transmitting 
input/output signals through external signal control interface. Different pins of 
the interface control different functions. Detailed instructions are listed on the 
above table. 
Under external analog quantity control mode, you can switch CC mode through 
pin 1 of the interface and switch CV mode through pin 6. 
3.21 Auto test function 
The IT8800 series electronic load delivers strong auto test functions, which can 
analog several tests. A total of 10 groups of test files can be edited, and each 
group test file has 10 steps. Therefore, a maximum of 100 steps can be edited 
and saved in EEPROM. 
NOTE 
In the following editing procedures, "Y indicates selected status. To cancel selected 
status, press numeric key of corresponding step again. 
Edit test files following steps below: 
Operation steps 
1.  Press [Shift] + [6] keys. 
PROGRAM 
Run   Recall   Edit 
2.  Operate 
  key and move to Edit. Press [Enter] key to enter editing 
test files. 
EDIT  PROGRAM 
Active Sequence=0987654321 
3.  Press numeric key to select test step and press [Enter] key. Active 
Sequence= 09876543YY (indicating that 1/2 step has been selected). 
EDIT  PROGRAM 
Active Sequence=09876543YY 
4.  Select whether pause is necessary for these two steps. If step 2 is to be