User`s manual

73
CHAPTER 3 COMMUNICATIONS BY THE MODEM FUNCTION
3
3.1 Overview
(6) Remote password check
If the remote password check has been set for the Q series C24 installed in the QCPU, the Q series C24
executes a remote password check when the programmable controller is accessed from an external device using
the Q series C24 modem function.
The following is an overview of the QCPU remote password function. For more details, see Page 86, Section
3.3.3.
(a) Remote password function
The remote password function allows / prohibits access to the QCPU from an external device via the following
modules.
• Q series C24
• Ethernet module
• Built-in CPU of Ethernet port
*1 In the case of the Ethernet module, the remote password function can be used for data communications connections
with an external device. For details, see the User's Manual (Basic) for the Ethernet module.
(b) Station where the remote password and remote password check are set
• In the case of a programmable controller system with one QCPU station
• In the case of a programmable controller system consisted of multiple QCPU stations
Set in the QCPU station which is the entrance of the programmable controller system as viewed from the
external device (the local station QCPU in the diagram below).
*1
*1 When set in a station other than the QCPU which is the entrance of the programmable controller system (relay station or
access station in the above diagram), access to other stations beyond the set station is prohibited.
QCPU
⋅
⋅
⋅
⋅
External device
access source
Modem
Public line
Modem
Q series C24
Remote
password
Remote
password
check
GX Developer parameter setting
Remote password
Module subject to the remote
password check
Communication executing the
remote password check
Communication using MC protocol
Communication using the GX Developer
QCPU
Ethernet
QCPU
Ethernet
QCPU
Ethernet
module
External device
access source
(Access station)
Modem
Public line
Modem
Q series C24
(Relay station)
Ethernet
module
(Local station)
Remote
password
Remote
password
check
Network System 1
Set in the local station to allow/prohibit access to
the network System 1 from the external device.
Not set in the relay station or access station.
(*)
Ethernet
module
Ethernet
module