2. SYSTEM CONFIGURATION
--------------------
MELSEC-A
(6) To eliminate incorrect
input
at
the
remote I/O modules, design
the
A2C
system considering the following.
(a) Measures on turning ON and OFF
the
power
1) When turning ON the power,
turn
ON
the
remote I/O modules
first, and then, turn ON
the
A2C. Or, turn ON
the
A2C and the
remote I/O modules
together
at the same time.
2) When
turning
OFF
the
power, turn OFF the A2C first, and then,
turn OFF
the
remote I/O modules. Or,
turn
them OFF
together
at
the same time.
IREMARKSI
Power supply for the remote I/O modules indicates the following.
(1)
I/O
module power
supply:
Power supplied to the
I/O
module power supply Is converted to
5 VDC inside the system and used in the internal circuit of the
I/O
module.
(2) Input external power
supply:
Power supply for input modules
(3) Output external power
supply:
Power supply for output modules
See the following manual for details.
A2CI/0
Module User's Manual
(b) Measures against momentary power failure
for
the
I/O module
Momentary power failure of the
power
supply of
the
I/O module may
cause incorrect input.
1) Cause
for
incorrect input due to momentary power failure
The I/O module hardware converts the I/O module
power
supply
(24 VDC) to 5 VDC inside the module.
If momentary power failure
occurs
in
the
I/O module, incorrect
input
occurs
if I/O refresh is executed within duration (A) shown
below
because:
(Time from occurrence of external
power
supply
OFF to turning OFF of internal 5VDC)
> (ON to OFF response
time of
input
module).
I
•
-
OFF
ON
OFF
ON
OFF
-
Externalsupply 24 VDC
(for I/O module power supply
and
input
external
power
supply)
Inside5VDC
Input (Xn)
ON
(A)
2-5
Whenthe input
external
powersupplyisturnedoff,
input (Xn)turnsoffafterthe ON-OFF responsetime
ofthe
input
module.
To Next Page
Loading...
