Contemporary Research TD960801-0MC - Manual (Page 25)

TD960801-0MC
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mounting into a larger industrial enclosure. As an option, the
EXTEND-A-BUS can be DIN rail mounted by purchasing the
appropriate kit. The EXTEND-A-BUS has two ports, one for
the CAN network and the other for the ARCNET backbone.
The device can be powered from either a low voltage AC or DC
power supply.
3.2.1 CAN Port
One electrically isolated CAN port has been provided capable of
operating to the DeviceNet physical layer specification. This
was done to minimize ground loop problems while providing
isolation to the ARCNET backbone. The port conforms to the
DeviceNet specification for a five position unsealed connector.
One CAN segment, conforming to the electrical restrictions of
the CAN segment, attaches to this port. In a similar method,
additional CAN segments are attached to other EXTEND-A-
BUS CAN ports. The only restriction is that all CAN
compliant devices on the complete network have unique MAC
IDs.
3.2.2 ARCNET Port
On the coaxial cable model, a BNC connector has been
provided. On the fiber optics model, two ST connectors are
provided-one for transmit (TX) and one for receive (RX). The
coaxial port is of the high impedance type (-CXB) allowing for
up to eight devices on one coaxial cable segment. A BNC
terminator (BNC-TER) and a BNC Tee connector (BNC-T) are
provided to facilitate connections to other bridges on the
ARCNET backbone. The ARCNET port operates at 2.5 Mbps.
Each EXTEND-A-BUS requires a unique ARCNET node ID
which has no meaning to the CAN segments. Node ID’s are
automatically assigned by the EXTEND-A-BUSes themselves
using an arbitration scheme upon power up.