LS Industrial Systems XBC-DR10E - 10.4 Troubleshooting Examples

Chapter 10 Maintenance
XBC E-Type Main Unit 10-11 Ver. 1
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10.4 Troubleshooting Examples
Possible troubles with various circuits and their corrective actions are explained.
10.4.1 Input circuit troubles and corrective actions
The following describe possible troubles with input circuits, as well as corrective actions.
Condition
Cause
Corrective Actions
Input signal
doesn’t turn
off.
Leakage current of external device
(Such as a drive by non-contact switch)
 Connect an appropriate resistor and
capacitor, which will make the voltage lower
across the terminals of the input module.
 CR values are determined by the leakage
current value.
− Recommended value C : 0.1 ~ 0.47㎌
R: 47 ~ 120 Ω (1/2W)
Input signal
doesn’t turn
off.
(Neon lamp
may be still
on)
Leakage current of external device
(Caused by a limit switch with neon lamp)
Input signal
doesn’t turn
off.
Leakage current due to line capacitance of
wiring cable.  Rewire the power supply on the external
device side as shown below.
Input signal
doesn’
t turn
off.
Leakage current of external device (Caused
by switch with LED indicator)
 Connect an appropriate register, which will make the
voltage higher than the OFF voltage across the input
module terminal and common terminal.
C
AC
input
R
~
C
AC input
R
~
C
External device
AC
input
R
Leakage current
AC input
~
AC input
~
DC
input
R
DC input
R