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58
When an inductive load is connected to the input or output of the CPU, it is
necessary to connect a surge suppressor or a diode in parallel with the load,
as shown below, to absorb the counter-electromotive force produced by the
load.
L
Surge suppressor
OUT
COM
Relay, or triac
output
COM
IN
DC Input
L
Diode
L
OUT
COM
Relay, or transistor
output
+
Diode
Resistor: 50
W
Capacitor: 0.47
m
F
Voltage:
200 V
Diode: Must
withstand
voltages more
than three times
the load voltage
and an average
current of 1 A
Output Loads
Be sure to take appropriate measures when any electrical device likely to
produce noise is connected to the CPU as a load. For example, electromag-
netic relays and valves generating noise of more than 1,200 V require noise
suppression. For AC noise sources, connect a surge suppressor in parallel
with the coil of each device. For DC noise sources, connect a diode in paral-
lel with the coil of each device. When mounting a CPU and an Expansion I/O
Unit on a control panel, be sure to completely ground the intermediate
mounting plate. The mounting plate must be finished with high-conductivity
plating to ensure noise immunity.
R
R
–
+
Surge
suppressor
AC power source
DC power source
Diode
Inductive Load Surge
Suppressors
Preventive Measures
Section 3-4
Содержание SYSMAC C20P
Страница 1: ...Cat No W167 E1 4A C20P C28P C40P C60P SYSMAC Programmable Controllers...
Страница 2: ...P type Programmable Controllers Installation Guide Revised July 1994 C20P C60P C60P C20P...
Страница 3: ...iv...
Страница 5: ...vi...