AutomationDirect CLICK Series - Page 228

Types of Additional Transient Protection
DC Coils:
The most effective protection against transients from a DC coil is a flyback diode. A flyback
diode can reduce the transient to roughly 1V over the supply voltage, as shown in this example.
Oscilloscope
24 VDC
DC Flyback Circuit
Sinking
Sourcing
+
_
30
25
20
15
10
5
0
-5
Volts
Many AutomationDirect socketed relays and motor starters have add-on flyback diodes
that plug or screw into the base, such as the AD-ASMD-250 protection diode module and
784-4C-SKT-1 socket module shown below. If an add-on flyback diode is not available for
your inductive load, an easy way to add one is to use an AutomationDirect DN-D10DR-A
diode terminal block, a 600VDC power diode mounted in a slim DIN rail housing.
DN-D10DR-A
Diode Terminal Block
AD-ASMD-250
Protection Diode Module
784-4C-SKT-1
Relay Socket
CLICK PLC Hardware User Manual, 5th Edition, Rev. F – C0-USER-M
3–35
Chapter 3: Installation and Wiring