On-Board Isolated Digital Input; Figure 2-3: Digital Input Connector Pin Assignments; Table 2-2: Digital Input Connector Signal Description - Advantech UNO-2050 User Manual

2.4 On-board Isolated Digital Input

The UNO-2050 has 8 isolated digital input channels designated
DI0~DI7.
Pin Assignment
The connector type of UNO-2050 is plug-in screw terminal block that
enables you to connect to field I/O devices directly without additional
accessories. Figure 2-3 and Table 2-2 shows its pin assignment as well
as signal description.

Figure 2-3: Digital input connector pin assignments

Table 2-2: Digital input connector signal description

Signal Name Reference
DI <0...7>
COM
Isolated Inputs
Each of isolated digital input channels accepts 10 ~ 50 V
inputs, and accepts bi-directional input. It means that you can apply
positive or negative voltage to an isolated input pin (Vin). All eight
channels share one common pin (COM). Figure 2-4 shows how to
connect an external input source to one of the UNO-2050's isolated
input channels.
1 2 UNO-2050 User's Manual
Isoated DI
Direction
COM Input
- Input
Description
Isolated digital input signals
External common input of DI
DC
voltage