Ratio Of External Devices To A Pc Cpu - Mitsubishi Electric AJ71C24-S6 User Manual

2. SYSTEM CONFIGURATIONS
MELSEC-A
2.3.3
2
:
1
ratio of external devices to a PC CPU
(1) The system configuration for a 2 : 1 ratio of external devices (such as
a computer) to a PC CPU is shown in Fig. 2.4 below.
(Mode: [ ] to [
1)
in the figure indicates the range of setting designated
with the mode setting switch of an AJ71C24 (see Section 4.3.1).
(A combination of two systems each of which has a 1 : 1 configuration.)
External device External device
(such as a com- (such as a com-
puter, printer, CRT) puter, printer, CRT)
(Mode:
1
to
8)
1
Toexiens& base Computer liAk module RS4Z interfacs
AJ71 C24
(1) One of the two interfaces is set to a dedicated protocol 1, 2, 3, or
4.
The other is set to a no-protocol/bidirectional mode.
(2) The use of the US-232C and the US-422 interfaces differs in that the
US-422 is used to connect long distances (up to 500 m (1 640.5 ft))
and the RS-232C is used to connect short distances (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.
Fig. 2.4 System Configurations (Ill)