Caution
Do not allow the voltage on the isolated inputs to exceed 30 VDC. Doing
so will damage the IC-317x.
Figure 6. 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-317x 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.
IC-317x User Manual
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© National Instruments
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