Rockwell Automation 1762-Lxxxx MicroLogix 1200 Programmable Controllers - Manual (Page 38)

Publication 1762-UM001G-EN-P - March 2011
3-4 Wire Your Controller
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 used. See Table 3.2 for recommended suppressors. As shown below,
these surge suppression circuits connect directly across the load device.
Suitable surge suppression methods for inductive ac load devices include a
varistor, an RC network, or an Allen-Bradley surge suppressor, all shown
below. These components must be appropriately rated to suppress the
switching transient characteristic of the particular inductive device. See the
table on page 3-5 for recommended suppressors.
+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
+24V dc
IN4004 Diode
Relay or Solid
State dc Outputs
24V dc common
VAC/DC
Out 0
Out 1
Out 2
Out 3
Out 4
Out 5
Out 6
Out 7
COM
(A surge suppressor
can also be used.)
Surge Suppression for Inductive ac Load Devices
Output Device Output Device Output Device
Varistor RC Network
Surge
Suppressor