Omron C-series - Manual (Page 31)

4-4 Section Wired Remote I/O Systems
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4-4 Wired Remote I/O Systems
Wired Remote I/O Master Units, Remote I/O Slave Units, and Remote Terminals
can be directly connected with RS-485 cable, which has a maximum transmis-
sion distance of 200 m. In order to extend the transmission distance and/or to
reduce noise interference, a pair of AL007-P Link Adapters can be used to insert
an optical link between any two Remote I/O Units/Remote Terminals. The follow-
ing example shows two Wired Remote I/O Units connected by optical fiber cable
by using a pair of AL007-P Link Adapters.
Link Adapter
AL007-P
Master, Slave, or
Remote Terminal
Optical fiber (APF/PCF)
Link Adapter
AL007-P
Master, Slave, or
Remote Terminal
RS-485 cable RS-485 cable
The Link Adapters must always be used in pairs, as they convert between wire
and optical signals, thereby allowing optical transmission between Units which
cannot themselves be connected directly to optical fiber cable. The entire Sub-
system, from Master to terminator, must be connected in series, with no branch-
ing. Up to 8 Link Adapters (4 pairs) can be used for each Master. The following
diagram illustrates an acceptable configuration for a Wired Remote Master Sub-
system, using the maximum of 8 Link Adapters for one Master. Note that all Units
are connected in series and all Link Adapters are used in pairs.
Wired Slave Wired Slave
Link Adapter
AL007-P
** Optical fiber
(APF/PCF)
* RS-485
cable
Link Adapter
AL007-P
Link Adapter
AL007-P
Link Adapter
AL007-P
Wired Slave Wired Master
Link Adapter
AL007-P
Wired Slave
Link Adapter
AL007-P
Link Adapter
AL007-P
Terminator
Link Adapter
AL007-P
Link Adapter
AL007-P
Wired Slave
* **
**
**
* *
* * *
*
* * ** *
Maximum cable length for any single section of optical cable is 20 m for all-plas-
tic optical fiber cable (APF) and 200 m for plastic-clad optical fiber cable (PCF).
To take full advantage of an optical link, shorten wire links as much as possible,
even to the point of placing the Link Adapter on the same control panel as the
Remote I/O Unit/Remote Terminal.