2.3.2 1 : N Ratio Of An External Device To Pc Cpus - Mitsubishi Electric AJ71C24-S6 User Manual

2.
SYSTEM CONFIGURATIONS
MELSEC-A
2.3.2 1 : n ratio of an external device to PC CPUs
(1) The system configurations for a 1 : n (up t o 32 stations) ratio of an
external device (such as
a
computer) to PC CPUs are shown in Fig. 2.3
below.
(Mode: [ ] to [ I ) in the figure the range of setting set with the mode
settina switch of an AJ71C24 (see Section 4.3.1).
\system configuration I
I
The external device is connected to the AJ71C24 modules using
the RS-232C
Set all AJ71 C24s to the
device
same protocol.
(computer)
RS-232C interface
Computer link modules
AJ71C24
I
I
PC
0
module
RS-232C inierface
/
' - , + '
' - - - - - -
i 1
I
I
RS-422 mterface
RS-422 cable
RS-422 interface RS-422 cable
RS-422 interface
Maximum of 32 stations
l ~ y s t e r n configuration 21 The external device is connected to the AJ71C24 modules using
the RS-422
device
(computer)
RS-422 interface Computer link modules
RS-422 cable AJ71C24
C P U
0 0 0 0
module
*
Setthe RS-422 of all AJ71C24s
to the same protocol.
(Mode. 1 to 8)
1
0
module
1
i i
' - - - - - - i
/
RS-422 interface RS-422 cable RS-422 interface RS-422 cable RS-422 interface
Maximum of 32 stations
4
(1) When the mode setting is 5 to 8, the RS-232C interface which is not
used for the multidrop link can be used for communications with a
computer, a printer, or a CRT in a no-protocolibidirectional mode.
(2) Use of the RS-232C and the RS-422 interfaces differs in that the
RS-422 is used to connect long distances (up to
500
m (1640.5 ft))
and the RS-232C is used to connect short distances (up to maximum
of 15 m (49.2 ft)).
(3) To have the RS-232C communicate over a distance greater than 15
m (49.2 ft), use a modem or RS-232ClRS-422 converter between the
external device and the AJ71C24.