FUNCTIONAL DESCRIPTION:

DS200AAHAH1AED is an ARCNET LAN Connection Board manufactured and designed by General Electric as part of the Mark V LM Series used in GE Speedtronic Control Systems. The ARCNET Connection Board (AAHA) provides the interface connection for ARCNET cables linking to the IO cores and HMI. Two BNC connections (channels A and B) are provided. One plug connector, the APL connector, is provided for communication with the boards containing the ARCNET drivers in . The APL connector links the AAHA board with the APL or BPL connector on the PANA board. Two AAHA boards are in location 6 of . One AAHA labeled AAHA1 in Appendix B, is for the Stage Link between and the operator interfaces. When both BNC connectors on this board are used, either two independent Stage Links can be connected to one controller or another controller can be connected to the Stage Link. The APL connector on AAHA1 connects to the APL connector on PANA. The second AAHA, labeled AAHA2 in Appendix B, connects to the COREBUS link that allows the Control Engine to communicate to the IO cores. COREBUS is the name of the internal ARCNET link for the Mark V LM controller IO communications. The APL connector on AAHA2 connects to the BPL connector on PANA.

FEATURES:

Topology: ARCNET supports both bus and star topologies. In a bus topology, all devices share a common communication medium, while in a star topology, each device is connected to a central hub.

Data Transfer Rate: ARCNET typically operates at speeds of 2.5 Mbps (Megabits per second) or 10 Mbps, depending on the version and implementation. It might not be as fast as some modern LAN technologies but was suitable for its time.

Medium Access Control: ARCNET uses a token-passing protocol for medium access control. A token is passed from one node to another, allowing the node holding the token to transmit data.

Cabling: The cabling used in ARCNET can vary, but it commonly employs coaxial cables. The type of cable and connectors used may depend on the specific implementation and version of ARCNET.

Network Size: ARCNET networks can support a limited number of nodes, typically ranging from a dozen to a few dozen devices. This makes it suitable for smaller networks.

Addressing: ARCNET devices are assigned unique addresses to enable communication within the network. These addresses are used to identify the source and destination of data packets.

Reliability: ARCNET is known for its deterministic and predictable behavior, making it suitable for real-time applications. The token-passing protocol helps ensure controlled access to the network.

Protocol Stack: ARCNET has its protocol stack, which includes the physical layer, data link layer, and a portion of the network layer. It is not directly compatible with the www.cniacs.com more common TCP/IP protocol stack.