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7 COMMUNICATIONS BY THE MODEM FUNCTION
7.1 Overview
Remote password check
If the remote password check has been set for C24, the C24 performs a remote password check when accessing to the
programmable controller from a target device using the C24 modem function.
The following is an overview of the CPU module remote password function.
Page 155 Applicability of remote password function
■Remote password function
The remote password function allows/prohibits access to the CPU module from a target device via the following modules.
•C24
• Ethernet module
• Built-in Ethernet port CPU
In the case of the Ethernet module, the remote password function can be used for data communications connections with a
target device. For details, refer to following manual.
MELSEC iQ-R Ethernet User's Manual (Application)
■Station to which the remote password and remote password check are set
• When a programmable controller system with one CPU module station
• When a programmable controller system consisted of multiple CPU module stations
Set to the CPU module station (the CPU module on the host station in the figure below) which is the entrance of the
programmable controller system as viewed from the target device.
When set to a station other than the CPU module which is the entrance of the programmable controller system (relay station
or access station in the above figure), access to other stations beyond the set station is prohibited.
RCPU
C24
Parameter setting with Engineering tool
Target device
access source
Remote password
Module subject to the remote
password check
Public line
Modem
Remote
password
check
Modem
Remote
password
Communication executing the
remote password check
Communication using MC protocol
RCPU C24
RCPU RCPU
Ethernet
Set in the host station to allow/prohibit access to
the network system 1 from the target device.
Remote
password
check
Remote
password
Public line
Modem
(Host station)
Modem
Ethernet
module
Target device
access source
Ethernet
Ethernet
module
Ethernet
module
Ethernet
module
(Access station)
(Relay station)
Not set in the relay station or access station.
Network System 1
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