2:N Ratio Of External Devices To Pc Cpus - Mitsubishi Electric AJ71C24-S6 User Manual

2. SYSTEM CONFIGURATIONS
MELSEC-A
2.3.4
2:n ratio of external devices to PC CPUs
(1) The system configuration for a 2 : n (up to 32 stations) ratio of external
devices (such as a computer) to PC CPUs is shown in Fig. 2.5 below.
(Mode:
[ I
to [
I)
in the figure indicates the range of setting set with the
mode setting switch of an AJ71C24 (see Section 4.3.1).
4
(A combination of two systems one of which has a 1 : 1 configuration and the other has
;
1 : n configuration.)
Enernal device1 External device2
(such sr campuler,
(computer)
*
Set the RS-422 of all AJ71C24s to
printer, CRT)
the same
protocol.
RS-232C interface RS-422 interface
RS-232C cable RS-422 cable
Computer link modules
1 to 8)
AJ71 C24
pc
Cp"-"
m / '
.232C interface
/
-
L - - - - - - -
US-422 interface RS-422 cable RS-422 interface
-
RS-422 cable RS-422 interface
Maximum of 32
stations
(1) One of the two interfaces of the AJ71C24 which is connected to the
external devices is set to a dedicated protocols 1, 2, 3, or 4. The
other is set t o a no-protocol/bidirectional mode.
(2) 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-protocol/bidirectional mode.
(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 AJ71 C24.
Fig. 2.5 System Configurations (IV)