Design of COLAN II, a control oriented local area network

Graduation date: 1988This paper describes the design and implementation\ud of COLAN II, a control oriented local area network (LAN).\ud COLAN II employs a bus interconnection structure and\ud a token passing method to control the access to the bus.\ud Major emphasis of the work is on the system structure and\ud the software operating system.\ud COLAN II consists of several nodes and a system bus.\ud The system bus uses the EIA RS-485 standard for\ud asynchronous communication. RS-485 has a higher data rate\ud and a lower error rate than conventional RS-232C. Each\ud node in COLAN II consists of an RS-485/RS-232C converter,\ud a Sibec II single board microcomputer, and an IBM\ud personal computer as a host.\ud The COLAN II software supports two interrupt\ud controlled serial ports; one to the network and the\ud another to a local host. The nodes in COLAN II can\ud communicate with one another using one of the three\ud packet-s: command packets, message packets, and text/data\ud packets. The software also supports node level application\ud programs suitable for control purposes