IDEC MICROSmart FC6A Series User Manual page 181

Power Supply Precautions
When supplying the power to the CPU module and to the expansion interface module (expander) with different power supplies, turn the modules

on and off in the order in the following table. An error may occur on the CPU module if the power on order or the power off order is mistaken.
Power Supply
Turn on the expansion interface module (expander) and the CPU module at the same time, or in expansion interface
Power on
module (expander)  CPU module order
Turn off the expansion interface module (expander) and the CPU module at the same time, or in CPU module 
Power off
expansion interface module (expander) order
Expansion interface module (expander)
main power
CPU module main power
When the CPU has suffered a power interruption and restarts, RUN/STOP follows the function area settings.

When the expansion interface module (expander) has suffered a power interruption, the CPU maintains its RUN/STOP status regardless of that
power interruption.
The other cartridges and the HMI module operate regardless of whether or not the expansion interface module is powered.
This section describes items that are particular affected by a power interruption of the expansion interface module.
Expansion interface module (expander)
main power
CPU module main power
Expansion module I/O
(Basic Expansion Side)
Expansion module I/O
(Expansion Interface Side)
If the expansion interface module (expander) main power supply is on and the CPU module main power supply is off, the expansion modules on

the expansion interface side are set to the reset status. Please note that during the reset status, the analog I/O module and PID module LED
indicators are on. This is not a malfunction.
ON
OFF
ON
OFF
0 s or longer
ON
OFF
ON
OFF
ON
OFF
ON
OFF
FC6A S MICROS U
ERIES MART
Order
0 s or longer
I/O for all expansion modules is off
when the expansion interface
module (expander) main power is off.
' M FC9Y-B1722
SER S ANUAL
2: P S
RODUCT PECIFICATIONS
2-145