The simulation panel and message word tester were used as part of training and testing by the operators and engineers who worked with the computer system that controlled the high voltage power distribution for NSW, Australia. Transgrid, the organisation that donated these cabinets, oversees and coordinates high-voltage electricity transmission in NSW. They are one of the companies that were formed to take over the duties of the former State Electricity Commission.

The TOSBAC Series 7/70E System, of which these objects form a part, is a Supervisory Control and Data Acquisition (SCADA) system designed and marketed by Toshiba. It runs TREX 2 (Toshiba Real-time EXecution) which is a special operating system for SCADA. While the TOSBAC and TREX comprise a computer system designed for general control application, this system was especially commissioned to run the State grid in NSW. It was purchased in 1982 and was running by 1985. DAC, (Data Acquisition and Control) as it is known by the Transgrid engineers who operate the system, is the third computer system to have been used to control the grid. The first was an analogue computer from Leeds and Northrop called George which was installed in the mid 1960s, and the second was a PDP/11 called Little George which ran from 1978 to 1985/6 when DAC was brought on line.

The TOSBAC system illustrates the use of computers to implement sophisticated control of a major public utility, and the importance of computer systems to our technological infrastructure. It was still in use up until 2003 and had been controlling NSW's high-tension transmission for the better part of twenty years. Prior to the grid being set up, power stations had to be built at the site of the power requirement. For example the Powerhouse Museum currently resides in the former power station built to supply electricity to Sydney's tram system. The understanding of power transmission has had implications for computing history. American scientist and engineer Vannevar Bush built his famous differential analysers in order to perform the calculations necessary to understanding the behaviour of transient signals in electricity transmission lines.

Moreover, this computer system represents an essential aspect of industrial and technological practice: control. From the governors used with industrial steam engines in the 1800s through to the operating system on personal computers, all technology requires a control system. Electricity is one of the most valuable and volatile elements of modern life. A highly sophisticated and reliable method of control is required to enable the safe delivery of electricity. The TOSBAC system is a significant example of a control system designed to manage an often unpredictable but essential commodity. The simulation panel was part of this control system as it enabled engineers to play-out many scenarios in isolation and thus exercise control over many situations that could occur with the actual delivery of electricity.

Damian McDonald
October 2007

Toshiba was formed in 1939 with the merger of two companies: Shibaura Engineering Works and Tokyo Electric. The merged company - Tokyo Shibaura Denki - was nicknamed Toshiba, and in 1984 the company was officially renamed the Toshiba Corporation.

The Message Word Tester (MWT) is a maintenance tool for the TOSMAP subsystem of the Toshiba 770E computer system. The functionality of the MWT was built into the basic firmware in the TOSMAP system. A dedicated socket was provided for its connection to CALMB1 card, and an associated miniature toggle switch for power. Depending where it was connected, a different overlay was used that defines the switch functionality. The MWT was very effective in monitoring packet contents on the serial communications between the master computer and the Remote Terminal Units (RTU). The other main use that Transgrid used the MWT for was reading the values in memory. This permitted checking of calibration of analogue inputs without contacting someone at the master computer.

The simulation panel, message word tester, and miniature direct wired testbox are part of a system which was commissioned to run the State Grid in NSW. It was purchased in 1983 and was running by 1985.

DAC (Data Acquisition and Control), as it is known by the Transgrid engineers who operate the system, is the third computer system to have been used to control the grid. The first was an analogue computer from Leeds and Northrop called George which was installed in the mid 60s and a PDP/11 called Little George which ran from 1978 to 1985/6 when DAC was brought on line.

Simulation panel, word tester, and miniature direct wired testbox, used with TOSBAC (Toshiba Scientific and Business Computer) computer system, metal / plastic / electronic components, made by Toshiba Corporation, Tokyo, Japan, 1983, used by Transgrid NSW, Australia, 1985-2003

The simulation panel has a metal case, five rows of toggle switches (ninety switches in all), three rows of which have LED lights above them (red above, green below), and twenty four dials set toward the front of the unit. The rear of the unit has four large serial port connections.

The word tester unit has a black metal casing with a silver metal plate on the top face. There are eight rebates cut into the metal plate in which sit eight toggle switches with an LED light above them all with unique testing functions. There is a data transfer cable leading into the top right corner that connects to a computer. There is also a power cable at the rear of the unit. This piece of equipment was used to test the programs of the TOSBAC computer.

The testbox is a one-off that was built to test the functionality of the Miniature Direct Wired (MDW) controls which interface between the DAC system and the HV switchgear. The MDW has relay based logic with the operator interface provided on a mosaic panel, originally located in the control room. M.O.I. - motor operated isolator. It was used by Transgrid engineer Colin Handel.

Made: 1983

Simulation panel: SIMULATION PANEL; Control & return; Single indication; Pulse accumulator; Analogue

Message word tester: MESSAGE WORD TESTER for TCM and TCR; Functions; Mode code; Group add; Section A; Word add; Section B

2008/58/4

1983

300 mm

610 mm