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The LINKnet* option provides distributed I/O capabilities for the 723 control system. The LINKnet I/O modules are well suited for non-time-critical control functions like sequencing and monitoring. Other manuals that may prove helpful are: 02007 DSLC Digital Synchronizer and Load Control 02758 723 Hardware Manual 02784 723 Software/DSLC Compatible 02785 723 Software/Analog Load Share Network Architecture An I/O network consists of a 723 LINKnet channel, which provides independent network trunks of up to 60 I/O modules. The LINKnet I/O modules, or nodes, on each trunk are attached to the 723 via a single twisted pair wire. Each LINKnet I/O module has two rotary switches that are used to set its network address. On installation, these switches must be dialed so that the I/O module's number (1 to 60) matches the network address defined for this I/O module in the application program. The I/O modules may be placed in any order on the network, and gaps are allowed in the address sequence. Hardware Each network consists of one LINKnet channel of a 723 and many I/O modules. The I/O modules include thermocouple, RTD, (4 to 20) mA, and discrete input modules, as well as (4 to 20) mA and relay output modules. All of the analog modules consist of six channels per module. The relay output module contains eight channels, and the discrete input module has 16 channels. Each I/O module is housed in a plastic, field termination module-type package for DIN rail mounting. The LINKnet I/O modules can be mounted in the control cabinet or in any convenient location in the vicinity of the engine or turbine that meets the temperature and vibration specifications. Each I/O module must be grounded to the DIN rail through a grounding block (Woodward part number 1604-813). All LINKnet I/O modules communicate with the 723 through shielded twisted pair wiring. The specifications for the LINKnet system require that listed level V type cable be used. The network may be wired directly from I/O module to I/O module, as shown in Figure 1-1, or the I/O modules may be connected to the network via stubs, as in Figure 1-2. A termination network (Woodward part number 9905-760) must be installed at the last LINKnet I/O module on the network. There is no polarity associated with the network wiring. For optimum EMC performance, the network cable shield should be landed at each I/O module, and the exposed wire length limited to 25 mm (1 inch). At the 723, the outer insulation should be stripped and the bare shield landed to the chassis.