Allen-Bradley SLC 500 1747-L40 - Page 20

20 SLC 500™ Fixed Hardware Style Controllers
Publication 1747-IN008B-MU-P
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 you connect an SLC 500 controller dc output to an inductive load, we
recommend that you use a 1N4004 diode for surge suppression, as shown in the
illustration that follows.
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.
OUT 1
OUT 5
OUT 6
OUT 7
OUT 2
VAC/VDC
OUT 0
OUT 3
COM
OUT 4
Snubber
+ dc or L1
dc COM or L2
ac or dc
Outputs
OUT 1
OUT 5
OUT 6
OUT 7
OUT 2
VAC/VDC
OUT 0
OUT 3
COM
OUT 4
1N4004 Diode
+24V dc
24V ac common
Relay or Solid State
dc Outputs
Surge Suppression for Inductive ac Load devices
Output Device Output Device Output Device
Varistor
RC Network
Surge
Suppressor