Chapter 14 Troubleshooting
13-9
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14.4 Cases
Here describes the trouble type and measures for each circuit.
14.4.1 Input Circuit Error Type and Corrective Actions
Here describes the trouble examples of input circuit and its measures.
Phenomena
Causes
Measures
Input signal
not OFF
Leakage current of external device
(In case of running by approach switch)
Input signal
not OFF
(sometimes
neon lamp
ON)
Leakage current of external device
(run by limit switch with neon lamp)
y
Connect the proper resistance and
capacity so that the voltage between
terminals of input module is below return
voltage.
y
CR value is determined by leakage
current.
−
Recommended C : 0.1 ~ 0.47Uf
R : 47 ~ 120
Ω
(1/2W)
or make the circuit independently and install
a separate circuit.
Input signal
not OFF
Leakage current by capacity between wiring
cables
y
Install the power on the external
device as below.
Input signal
not OFF
Leakage current of external device
(run by switch with LED indicator)
y
Connect the proper resistance as
below so that the voltage between input
module terminal and common terminal
exceeds OFF voltage.
Input signal
not OFF
y
Circulated current by double power
y
In case of E1 > E2, circulated.
y
Double power --> single power.
y
Connect purified current prevent
diode.
(as below)
External
device
AC input
Leakage
current
External device
DC input
R
Leakage
current
DC input
L
E
E
C
External device
AC input
R
Leakage
current
C
External device
AC input
R
Leakage current
C
AC input
R
AC input
External
device
DC input
R
E1
DC input
L
E