Contemporary Control Systems QuickLink Active Hubs User Manual

QUICKLINK

A Line of External Fixed-Port Active Hubs for ARCNET® Local Area Networks

INST ALLA TION GUIDE

INTRODUCTION

The QuickLink (QL) Series of external fixed port hubs provides a low cost method of expanding ARCNET local area networks. These eight-port hubs provide the ultimate in reliability and flexibility for cabling ARCNET networks. A hub allows for the addition of a segment and support for distributed star topologies. The QL utilizes the same robust hub timing electronics found in the Contemporary Controls (CC) MODHUB series for modular active hubs. This includes precision delay line timing, digitally controlled timers for dependable operation and reduced bit jitter. Also, a watchdog timer is included to prevent hub lockup — eliminating the need to recycle hub power in the event of extraordinary electrical disturbance.

The QL operates from low-voltage AC, requiring a power voltage source in the range of 8 to 24 volts.

Active hubs increase the robustness of ARCNET networks. They maximize the distance that can be achieved on each cable segment ⎯ up to 2000 feet (610 m) feet on coaxial segments. They prevent interference to the network by squelching reflections caused by open or shorted cable segments attached to the hub. Unused hub ports need not be terminated. Active hubs allow for a distributed star topology, thereby minimizing the cabling required in a facility. Two or more QL hubs may be cascaded.

SPECIFICATIONS

Environmental

Operating temperature: 0°C to +60°C Storage temperature: –40°C to +85°C Relative humidity: 10 to 95%, non-condensing

Regulatory Compliance

CE Mark CFR 47, Part 15 Class A

Functional

Compliance: ANSI/A TA 878.1 Hub delay: 300 ns max @ 2.5 Mbps Unlatch delay time: 5.9 µs max @ 2.5 Mbps LED Indicators: ACTIVITY ⎯ green

Power Requirements

Input voltage: 8–24 Volts Input power: 6 VA Input frequency: 47–63 Hz

Mechanical

INSTALLATION

The QL was designed as a desktop unit and should be installed on a stable surface in a horizontal plane. Four rubber feet protect the mounting surface. Power is derived from a nominal 24 VAC source, either a local power

supply or the wall-mounted transformer provided with the QL. This transformer is normally for a 120 VAC mains, but (-E) models are supplied with

a 230 VAC transformer.

TD990300-0IH

Each transformer comes with a 6-foot cord molded into the transformer. The other end is stripped and tinned and must be secured to the two-position removable connector located on the QL. With power removed from the transformer, attach one wire to one of the terminals and the other wire to the remaining terminal. Polarity of the wires is of no concern. Once wired, plug the transformer into the appropriate wall socket to power up the QL.

Figure 1 — The QL can be powered by an external low-voltage transformer.

Figure 2 — The QL must have its companion transformer secondary

leads attached to its two-position removable connector.

The QL supports two transceiver types which are described below:

-CXS Coaxial Star

Typically, ARCNET is cabled with RG-62/u coaxial cable (with BNC connectors) in a star topology. Each network interface module (NIM) connects directly to a port on the QL hub. The coaxial star configuration provides the longest coaxial distance and simplified troubleshooting. A

-CXS port effectively terminates the end of a coaxial bus segment without the need of a passive terminator. With this configuration, the bus segment can support up to eight NIMs with a maximum segment length of 1000 feet (305 m).

-TPS Twisted-Pair Star

Unshielded or shielded twisted-pair wiring such as IBM Type 3 (#24 or #22 AWG solid copper twisted-pair cable or telephone wiring) can be used. External BALUNs are not required since CC’s twisted-pair NIMs and hubs have internal BALUNs. Twisted-pair is convenient to install; however, its attenuation exceeds coaxial, its noise immunity is less, and its maximum length between a node and a hub is lower. RJ-11 connectors are used with this cable. A -TPS port effectively terminates the end of a twisted-pair bus segment without the need of a passive terminator. With this configuration, the bus segment can support up to eight NIMs with a maximum segment length of 330 feet (100 m).