Omron C-series manual Wired Remote I/O Systems

Wired Remote I/O Systems Section 4-4

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

Link Adapter

AL007-P

Optical fiber (APF/PCF)

RS-485 cable

RS-485 cable

Master, Slave, or Remote Terminal

Master, Slave, or Remote Terminal

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 Master	*	Wired Slave
	*
Wired Slave		Link Adapter
		AL007-P

*	Link Adapter		**
	AL007-P
**				*
		Link Adapter
		AL007-P

Link Adapter	*	Link Adapter
AL007-P		AL007-P
		*
	*
Wired Slave		Wired Slave

*RS-485 cable

**Optical fiber (APF/PCF)

Link Adapter ** AL007-P

Link Adapter * AL007-P

Wired Slave

* Link Adapter ** AL007-P

Link Adapter * AL007-P

Terminator

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.

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