IEEE-488 1978 general purpose interface bus test

Abstract

The IEEE-488 General Purpose Interface Bus (GPIB) is the industry standard bus for electronic instrument communication between instrument and computer. Regardless of the manufacturer, instrument's function and communication protocol remains constant. Because industries emphasis continue to press for increased automation, therefore leading instrument manufacturer such as John Fluke, Hewlett-Packard and Polaroid have expanded their product time to include the GPIB. Defense electronics purchases continue to include GPIB-equipped instruments. As early as 1983, the Department of the Navy released a software GPIB test for use by Naval maintenance activities. In 1986 research begun at East Carolina University Department of Computer Science to expand, improve and speed up GPIB testing. Results were evaluated in Nov. 1987, by the Navy's Metrology Engineering Department, Corona California were found to improve existing GPIB test methods, it will be released to Naval activities through a GPIB software revision in spring 1988. Our methodology include development of closed-loop GPIB test module that requires minimal human interfacing with the instrument and computer while insuring test results and efficiency. Primary emphasis was placed upon binary decision tree for evaluating a GPIB's test results, keeping the test efficient with respect to real time environment and test evaluation parameters. In order to comply with industry's fiscal restrictions the software has been configured to allow future GPIB equipped instruments to be tested without any revision in the software structure. The computer used to develop the software was the John Fluke 1722AAP instrument controller the source code and data files were written with sufficient flexibility and generic commands to be easily used by other systems. Computer memory size, DBM ability are not significant, since system employ software overlapping technique. The data files, containing verified instrument commands, replies, and instrument module number have been coded such as to reduce storage requirement and secondary storage transfer time. Instruments which cannot respond across the GPIB but do receive commands and output stimula (listeners) are included in the testing, as well as instruments that receive commands and transmit data to computer. In the case of the latter, minimal technical expertise required by the operator when performing GPIB test as the computer transmits commands, accepts and evaluate received data, and output the test result. Testing time has been measured in milliseconds, well within the two minute time requirement imposed at the beginning of the work. The software will allow engineers and those personnel with sufficient technical expertise to continue testing, manually sending commands to an instrument over the GPIB and evaluate instrument changes and reply data.