LS Industrial Systems SV-iS7 PLC User Manual

Chapter 10 Troubleshooting
10-9
10.4.2 Output circuit troubles and corrective actions
The following describes possible troubles with input circuits, as well as their corrective actions.
Condition Cause Corrective Action
When the output
is off, excessive
voltage is
applied to the
load.
yLoad is half-wave rectified inside (in some
cases, it is true of a solenoid)
yWhen the polarity of the power supply is as
shown in , C is charged. When the polarity is ①
as shown in , the voltage charged in C plus ②
the line voltage are applied across D. Max.
voltage is approx. 2√2.
*) If a resistor is used in this way, it does not
pose a problem to the output element. But it may
make the performance of the diode (D), which is
built in the load, drop to cause problems.
y Connect resistors of tens to hundreds KΩ
across the load in parallel.
The load
doesn’t turn off.
y Current leakage by surge absorbing circuit,
which is connected to output element in parallel.
y Connect C and R across the load, which are of
resistors of tens KΩ. When the wiring distance
from the output module to the load is long, there
may be a leakage current due to the line
capacity.
When the load
is C-R type
timer, time
constant
fluctuates.
y Current leakage by surge absorbing circuit,
which is connected to output element in parallel.
y Drive the relay using a contact and drive the C-
R type timer using the since contact.
y Use other timer than the C−R contact some
timers have half-ware rectified internal circuits
therefore, be cautious.
R
Load
R
Load
C
C
R
Load
Leakage current
Output
~
C
R
Load
Leakage current
Output
~
X
T
Timer
Output
~
C
R


Load
D
~
C
R
Load
R
D
~

LS Industrial Systems SV-iS7 PLC Specifications

General

Brand	LS Industrial Systems
Model	SV-iS7 PLC
Category	Computer Hardware
Language	English