National Instruments 8-Channel Solid-State Relay (SSR) Digital Output NI 9485 - Manual (Page 11)

© National Instruments Corp. 11 NI 9485 Operating Instructions
Figures 4 and 5 show examples of using an external flyback diode
to protect DC inductive loads and an MOV to protect AC inductive
loads, respectively.
Figure 4. Contact Protection for DC Inductive Loads
CHa
CHb
Inductive
Load
NI 9485
Flyback Diode for
DC Inductive Loads
V
DC
+
–