User manual

915U-2 Wireless I/O Page 29
Page 29 User Manual
2.5.3 Digital Inputs
Each digital I/O channel on the 915U-2 can act as either an input or an output. The
input/output direction is automatically determined by the connections and configuration
of the I/O.
If you have an I/O channel wired as an input but operate the channel as an output. No
electrical damage will occur however, the I/O system will not operate correctly.
If operating the channel as an output and performing a “read inputs” on this location it
will indicate the status of the output.
Marked DIO1-8 the Digital inputs share the same terminals as the Digital outputs on the
915U-2 module.
A digital input is activated by connecting the input terminal to EARTH or Common,
either by voltage-free contact, TTL Level, or transistor switch.
Each digital input has an orange indication LED that will turn on when the input has
been connected to a GND or common.
Voltage Free Contact
Transistor
Switch Device
V+
V-
DIO1
DIO2
Common
915U-2
Discrete Input / Output Used as input
Figure 13 – Digital Input Wiring