User`s manual

151
CHAPTER 3 COMMUNICATIONS BY THE MODEM FUNCTION
3
3.4 Start-up of the Modem Function
When initiating the line connection from the partner device after the completion of initialization
● The connection channel on the Q series C24 side is set in the "modem function system setting" screen of GX
Configurator-SC.
● Abnormal processing when the partner device initiate the line connection is left entirely to the partner device. There is no
method on the Q series C24 side to check a line connection error occurrence at the partner device.
● When a remote password check is performed for the QCPU, normal completion of the unlock processing allows access
to data communication/ programmable controller thereafter.
(4) Precautions during the line connection
• Prior to data communication with external devices, determine when and which station will perform the line
connection (dialing) and line disconnection processing to the external device.
• Use the following method to perform the unlock processing for the QCPU remote password from the
opposite device.
• During communication using MC protocol, transmit the dedicated command to the Q series C24 side.
• When accessing the programmable controller using the GX Developer, perform the unlock processing on
the GX Developer screen when access begins. See Page 121, Section 3.3.7 (8) for what to do when the
unlock processing is completed abnormally.
• When reconnecting the line after disconnection, allow several seconds for the modem before turning on the
Connection request (Y11). If it (Y11) is turned on immediately after line disconnection, the modem may not
accept the first connection request, resulting in connection failure, and the user may be forced to wait for the
retry time to elapse.
(ON)
(OFF)
(OFF)
Y11
X10
X11
X12
*
0
Remote
password
Response
Communication using MC protocol
When connecting to the GX Developer
Unlock processing for
the remote password
Buffer memory for
connection
Address: 35H (53)
Connection
request
Initialization
completion
Dial in progress
Connection in
progress
RS-232 CD terminal
(Normal connection)
(Normal connection)
Reception
Password
(for system)
Response
Communication only
when connected with
GX Developer
Result code
receive
Set "Display a result code
using the AT command" in
the local station side modem.
*