Automationdirect.com DL06 - Page 66

DL06 Micro PLC User Manual, 3rd Edition, Rev. E
Chapter 2: Installation, Wiring, and Specifications
1
2
3
4
5
6
7
8
9
10
11
12
13
14
A
B
C
D
2-23
Example: Larger Inductive Load with Only Integrated Suppression
5HOD\
&RLO

9'&
2VFLOORVFRSH
)RUWKLVH[DPSOHDP$:
UHOD\LVXVHG$XWRPDWLRQ'LUHFW
SDUWQR6&(*9'&








9ROWV
Additional transient suppression should be used in both these examples. If you are unable
to measure the transients generated by the connected loads of your control system, using
additional transient suppression on all inductive loads would be the safest practice.
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