User`s guide

1-4

48VDC

Power

Supply

LPI-10

Interface

LPT-10

Node

additional

LPT-10

FTT-10

nodes

FTT-10

Node

LPT-10

Node

FTT-10

Node

LPT-10

Node

Figure 1.1 Free Topology Link Power System

LPT-10 Link Power Transceivers located along the twisted wire pair include integral

switching power supplies. These supplies regulate the power on the twisted pair to

+5VDC at currents up to 100mA for use by the Neuron Chip and the various sensors,

actuators, and displays. If a high current or high voltage device must be controlled,

then the +5VDC power can be used to trigger an isolating high current triac, relay, or

contactor.

The integral power supply does away with the need for a local AC-to-DC power

supply, charging circuit, battery, and the related installation and labor expenses. The

savings in money and time that results from eliminating the local power supply can be

up to 20% of the total system cost: the larger the system, the greater the savings.

Moreover, if standby batteries are used, then additional savings will be realized

throughout the life of the system since only one set of batteries will require service.

The link power system uses a single point of ground, at the LPI-10 module, and all of the

LPT-10 transceivers electrically float relative to ground. Differential transmission

minimizes the effects of common mode noise on signal transmission. If grounded sensors

or actuators are used, then either the communication port (CP) or the I/O lines of the

Neuron Chip must be electrically isolated.

Unlike bus wiring designs, the link power system uses a free topology wiring scheme

that supports star, loop, and/or bus wiring (figure 1.2). Free topology wiring has many

advantages. First, the installer is free to select the method of wiring that best suits the

installation, reducing the need for advanced planning and allowing last minute changes

at the installation site. Second, if installers have been trained to use one style of

wiring for all installations, link power technology can be introduced without requiring

retraining. Third, retrofit installations with existing wiring plants can be