Rockwell Automation 1766-Lxxxx MicroLogix 1400 Programmable Controllers User Manual - Manual (Page 43)

Rockwell Automation Publication 1766-UM001H-EN-P - May 2014 29
Wire Your Controller Chapter 3
When using spade lugs, use a small, flat-blade screwdriver to pry the finger-safe
cover from the terminal blocks as shown below. Then loosen the terminal screw.
Using Surge Suppressors Because of the potentially high current surges that occur when switching
inductive load devices, such as motor starters and solenoids, the use of some type
of surge suppression to protect and extend the operating life of the controllers
output contacts is required. Switching inductive loads without surge suppression
can
significantly reduce the life expectancy of relay contacts. By adding a
suppression device directly across the coil of an inductive device, you prolong the
life of the output or relay contacts. You also reduce the effects of voltage
transients and electrical noise from radiating into adjacent systems.
The following diagram shows an output with a suppression device. We
recommend that you locate the suppression device as close as possible to the load
device.
If the outputs are DC, we recommend that you use an 1N4004 diode for surge
suppression, as shown below. For inductive DC load devices, a diode is suitable. A
1N4004 diode is acceptable for most applications. A surge suppressor can also be
Finger-safe cover
44528
+DC or L1
Suppression
Device
DC COM or L2
AC or DC
Outputs
Load
VAC/DC
Out 0
Out 1
Out 2
Out 3
Out 4
Out 5
Out 6
Out 7
COM