Cautions And Corrective Actions For Input And Output Circuits - Mitsubishi Electric MELSEC-KOJIU Instruction Manual

b
3.5 Cautions and Corrective Actions for Input and Output Circuits
c
3.5.1 Cautions and corrective actions for input circuits.
-
Ex
1
2
Condition
Though triac is
not on, input
turns on.
Though triac is
turned off, input
fails to turn off.
~~
Though limit
switch is not
on, turns on.
Though limit
switch is
turned off,
input fails
to turn off.
Same as
example 2.
Table
3.5.1
Cause
Input is turned on by leak current from the
CR absorber used to protect triac from surge.
AC2-wiretypeproximity
Powet supply
AC 115 V
AR, AS,
AT
This occurs in AR, AS, or AT when leak
current excedds 4 mA.
When limit switch is provided with neon
lamp, input is turned on by leak current
caused by neon lamp.
Limit switch with
neon lamp
I----
1
n
AC 115 V
In case input signal line is wired long distance
in parallel t o other power line, etc., input
turns on because voltage is induced by induced
voltage from power line.
- - 1
n
I
I
AR
#
A
Corrective Action
Connect resistor or series
co-
mbination of resistor and capacitor
as shown below in order to reduce
input impedance so that voltage
across input terminals of input
unit is lower than input operation
"off' voltage.
Example: 15KS2
2w
Example: CR: 0.5pF +5Oa
Note: Determine R and CR values
depending on leak current
values
When only resistom is used,
more heat is generated.
If possible, use the
combination of resi$tor
and capacitor.
This combination prvduces
an effect also on lawe surne.