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FX2N-64CL-M CC-Link/LT Master Block
12.5
Prevention of erroneous inputs to and outputs from remote I/O module
In order to prevent erroneous inputs to and outputs from remote I/O modules, design the
system under consideration of the contents described below.
1) When setting the power to ON or OFF
Turn ON the power to remote I/O modules (power adapter or dedicated power supply) first,
and then start the data link.
Stop the data link first, and then turn OFF the power to remote I/O modules (power adapter
or dedicated power supply).
FX
-64CL-M
2N
(data link status)
Remote I/O module
(power supply status)
2) When the power is interrupted instantaneously in a remote I/O module
When the power (24V DC) supplied to a remote I/O module is interrupted instantaneously,
erroneous inputs may occur.
a) Cause of erroneous inputs due to instantaneous power interruption
The hardware of a remote I/O module converts the unit power (24 VDC) into 5V DC
inside, then uses it.
If instantaneous power interruption occurs in a remote I/O module,
(Time until 5V DC inside remote I/O module turns OFF)
As a result, if refresh is executed in the period shown in (A) below, erroneous inputs
occur.
(Erroneous inputs may occur especially while the input response time is set to high-
speed input type.)
Remote I/O module
(Unit power supply and external
power supply to input area)
Remote I/O module
(internal 5V DC)
Input (Xn)
Data link start
Executing
Stopped
ON
OFF
> (Response time for "ON → OFF" of input unit)
When the external power supply to
the input area is set to OFF, the input
(Xn) turns OFF after the response
time for "ON → OFF" of the input unit.
Data link stop
(A)
When the external power supply to the
input area is set to ON, the input
(Xn) turns ON after the response time
for "OFF → ON" of the input unit.
Troubleshooting 12
12-9
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