Table 18. Digital I/O Connector 2 Pin Descriptions (Continued)
Pin Number
Signal
Description
16
C
ISO
Common for isolated inputs and outputs
17
C
ISO
Common for isolated inputs and outputs
Wiring an Isolated Input
You can wire an isolated input to a sourcing output device.
Caution
Do not apply a voltage greater than 30 VDC to the isolated inputs.
Voltage greater than 30 VDC may damage the IC-3173 (IP67).
Figure 29. Connecting an Isolated Input to a Sourcing Output Device
V
REF
C
ISO
Industrial Controller
Input
Sourcing
Output
Device
Current
Limiter
Power Supply
+
–
Wiring an Isolated Output
The digital isolated output circuits source current to external loads.
When an inductive load, such as a relay or solenoid, is connected to an output, a large counter-
electromotive force may occur at switching time due to energy stored in the inductive load.
This flyback voltage can damage the outputs and the power supply.
To limit flyback voltages at the inductive load, install a flyback diode across the load. Mount
the flyback diode as close to the load as possible. Use this protection method if you connect
any of the isolated outputs on the IC-3173 (IP67) to an inductive load.
The following image shows an example of an isolated output wired to an external load with a
flyback diode installed across the load.
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IC-317x User Manual