Advantech APAX-5000 Series User Manual page 17

You can distinguish if the ID number is doubled by the front LED. When the LED color
is green, only 0 ~ 15 ID number is used (0 ~ 15 according to the rotary ID switch).
Once the LED color is orange, the ID number is doubled (16~31 according to the
rotary ID switch). Refer to figure below for its location and how to configure it.
DIP Switch Setting
Warning! Avoid two modules with the same ID number in the same system, or you
cannot see the module in the software utility. The LED on the front side
will flash four times if two or more modules have the same ID number in
one system. If this happens, simply change the ID number for these
conflicted modules and all of them can be found in utility again.
ID
16 ~ 31 according to the rotary ID swich
0 ~ 15 according to the rotary ID swich
9
LED Color
Orange
Green
APAX-5000 I/O Series User Manual