MITSUBISHI ELECTRIC QJ71C24N - Manual (Page 34)

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MELSEC-Q
1 OVERVIEW
(9) Remote password check function
(Details are explained in the User's Manual (Application) and the Reference Manual.)
(a) The remote password check function of the Q series C24 prevents users at
a remote location to access QCPUs illegally using the modem function of the
Q series C24.
(The remote password is checked in the following forms of data communication)
• Communication using the MC protocol
(The remote password check is not carried out in data communication
using the non procedure/bidirectional protocols.)
• Access to the PLC through GX Developer
The remote password function is one of the QCPU functions and used for
preventing illegal access to the QCPU by other users.
Use GX Developer to set a remote password for the QCPU in order to
activate the remote password function of the QCPU.
(b) If the Q series C24 is specified in the parameters of a QCPU as being
subject to the remote password check, the remote password can be
unlocked (canceled) using either one of the methods below, to allow data
communication from the external device. It is necessary to connect a line to
the modem first.
• When communicating using the MC protocol
Use the dedicated command for communication using the MC protocol to
unlock the remote password from the external device.
• When accessing the PLC through GX Developer
Unlock the remote password using GX Developer at the start of online
operation.
The remote password is automatically locked by disconnecting the line to
the modem.
Accessing
external device
Modem
Dialup line
Modem
QCPU Q series C24
Communication using the MC protocol
Communication through GX Developer.
GX Developer
Set the parameters to make
the Q series C24 as a subject to
the remote password check.
Remote
password
Remote
password
check