46 Rockwell Automation Publication 2080-UM002L-EN-E - November 2021
Chapter 4 Wire Your Controller
• Separate wiring by signal type. Bundle wiring with similar electrical
characteristics together.
• Separate input wiring from output wiring.
• Label wiring to all devices in the system. Use tape, shrink-tubing,
or
other dependable means for labeling
purposes. In addition to labeling,
use colored
insulation to identify wiring based on signal characteristics.
For example, you may use blue for DC wiring and red for AC wiring.
Use 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.
Figure 3
shows an output with a suppression device. We recommend that you
locate the suppression device as close as possible to the load device.
Figure 3 - Output with Suppression Device
If the outputs are DC, we recommend that you use an 1N4004 diode for surge
suppression, as shown in Figure 4 on page 47
. For inductive DC load devices, a
diode is suitable. A 1N4004 diode is acceptable for most applications. A surge
suppressor can also be used. See Recommended Surge Suppressors
on page 47.
These surge suppression circuits connect directly across the load device.
Wire Requirements
Wire Size
Type Min Max
Micro830/
Micro850/
Micro870
Controllers
Solid
0.2 mm
2
(24 AWG) 2.5 mm
2
(12 AWG)
rated @ 90 °C (194 °F)
insulation max
Stranded
0.2 mm
2
(24 AWG) 2.5 mm
2
(12 AWG)
+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