Data Sheet

Inputs
Each Input has two links which connect it to the isolated 12v supply. This provides a small
bias current to the opto-isolator which external volt free contacts can short out. In this
configuration the inputs are isolated from everything except each other as they have a
common 0v connection. This is normally what you will want, however if you need an input to
be totally isolated then remove both links from the pcb on that input. This will isolate the input
from all other inputs, but you will need to provide an external isolated voltage to the input (5v-
24v).
Note the following:
With the links in place, reading the inputs over MODBUS will read as 0 when nothing is
connected and 1 when the input is connected to closed contacts.
With the links removed, reading the inputs over MODBUS will read as 1 when nothing is
connected and 0 when an input voltage (5v-24v) is supplied.