A local area computer for data acquisition and control

A low cost control and data acquisition computer system was developed to be used as an element in distributed architecture control systems. It can be viewed as a low cost replacement for the CAMAC crate and its associated computer. This Local Area Computer (LAC) is based on the STD bus backplane, a low end industrial standard. Currently, it runs on a 8088 based processor card. Communication with other computers on the system is achieved through a specially designed SCSI-Ethernet controller, which can be programmed to allow sending of data only during a specified time slot. This mechanism avoids delays on the network due to collisions, and enables the LAC to dump it entire database at regular intervals for retrieval by one or several hosts. Software -written in C and running under the VRTX real time executive- mimics the easy access to the hardware typical of CAMAC modules, allowing interfacing to control system software developed at other laboratories. Most of the LAC components are off the shelf items. However, some peripherals specific to accelerators, such as high stability voltage references and change ADCs, were developed in house. 4 refs., 3 figs., 1 tab