Contemporary Control Systems AI-FR User Manual

AI-FR

Fixed Port Active Hubs for Redundant Fiber Ring Topology in ARCNET

INTRODUCTION

Traditionally, ARCNET has been cabled as either a star or bus network, but never as a ring. However, under certain conditions a ring topology is possible. The ring has merit when the goal is to provide redundant cabling so that continuity can be preserved in the event of cable failure. If one cable becomes disabled for any reason, another is still available to pass messages. It is for this purpose that the AI-FR has been developed and implemented to achieve fiber optic redundancy in an otherwise un-redundant networking technology.

The AI-FR utilizes the same robust hub timing electronics found in Contemporary Controls’ MOD HUB series of modular active hubs. This includes precision delay line timing, digitally controlled for dependable operation and reduced bit jitter.

The AI-FR is an application specific active hub that provides integrity status of the redundant fiber backbone. Redundant network topology — defined as a fiber optic ring with a local drop — is ideally established with three-port hubs, each incorporating the principle of fault monitoring.

A fiber backbone ring up to 2 km in size and employing up to four AI-FR hubs is possible. By decreasing the total fiber ring size, additional AI-FR hubs can be attached to the network allowing more devices to share the redundant ring.

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 Local Area Networks

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INST ALLA TION GUIDE

The AI-FR operates from either low voltage AC or DC power. For DC operation, a voltage source in the range of 10 to 36 volts is required. For AC operation, the source must be in the range of 8 to 24 volts. Redundant power supplies can be attached for critical applications.

The hub is available in two versions. The AI-FR/CXB hub provides fiber ring continuity with a coaxial bus local drop while the AI-FR/TB5 accommodates a drop established by twisted-pair bus.

SPECIFICATIONS

Electrical DC AC

Input voltage: 10–36 V Input power: 4 W 4 VA Input frequency: N/A 47–63 Hz

Fault Relay Contacts

Max current and voltage: 500 mA

Environmental

Operating temperature: 0°C to +60°C Storage temperature:

Data Rate

AI-FR hubs operate at 2.5 Mbps.

Timing

AI-FR delay time: 330 ns maximum at 2.5 Mbps Unlatch delay time: 11.9 µs at 2.5 Mbps

Optical Power Budget (-FOG 850 nm at 25°C)

50/125 microns 6.6 dB

62.5/125 microns 10.4 dB 100/140 microns 15.9 dB

Dimensions Compatibility

5.45" x 6.14" (139 mm x 156 mm) Compliant with ANSI/ATA 878.1

–40°C to +85°C

8–24 V

200 V

Shipping Weight Regulatory Compliance

2lbs. (.9kg) CE Mark

CFR 47, Part 15 Class A

Mechanical

TD675300-0ID

INSTALLATION

AI-FR hubs are intended to be panel mounted in an industrial enclosure or wiring closet with two #8 pan head screws (not provided). Optionally, a DIN rail mount can be used by purchasing a DIN rail mounting kit.

Electromagnetic Compliance

This equipment is intended for nonresidential use. Operation in a residential area is likely to generate electrical interference unless corrective measures are undertaken by the user.

Powering

AI-FR hubs require either low voltage AC or DC power via a four-pin removable keyed connector. Consult the specifications for power requirements. The various power options are explained below.

DC Powered

AI-FR hubs accept a voltage range of 10–36 VDC and draw a current value commensurate with 4-watt power consumption. Power conductors should be sized accordingly. Ground is directly connected to zero volts and the equipment chassis is isolated from zero volts. The input connections are reverse-polarity protected.

Figure 1 — DC Powered

Redundant DC Powered

Redundant diode-isolated DC power inputs are provided so the AI-FR can operate despite the loss of primary power. Either source must provide 4 watts, but the currents drawn from the two supplies may differ.

Figure 2 — Redundant DC Powered