National Instruments SCXI-1161 - Manual (Page 27)

Chapter 3 Signal Connections
SCXI-1161 User Manual 3-2 © National Instruments Corporation
Figure 3-1. Contact Protection Using a Flyback Diode for DC Inductive Loads
In addition, the module has pads on which you can place an arc
suppressor protection circuit to limit the voltage spike generated during
the switching of inductive loads. These pads are between the COM
position and the NO position and between the COM position and the NC
position of the relays.
To determine where to place each arc suppressor, refer to Tables 3-1
and 3-2, which indicate the channel and suppressor pad assignments.
Table 3-1. Arc Suppressor Placement, COM to NO
COM to NO
Channel Number
Transient Voltage Suppressor
Reference Designator
0 VR1
1 VR3
2 VR5
3 VR7
4 VR9
5 VR11
6 VR13
7 VR15
V
NC
COM
NO
VDC Inductive Load Flyback Diode
+
-