The normalized measured value is connected across the system bus to the display unit when the push-button for manual measuring in the front of a module is depressed. The signal is scaled to its correct value before A/D conversion and presentation on the digital display with the correct number of decimals.
Information concerning scaling factor and number of decimals is programmed on each channel board, and is connected to the system bus at the same time as the measured value. It is possible to program eight different factors with a 3-bit binary code, and the number of decimals can be 0, 1 or 2.
The display is normally dark and is only lit up when a push-button for manual measuring has been depressed, the displayed value will follow the fluctuations of the signal. When the push-button is released, the value will remain unchanged for about five seconds.
Honieiask: Ex. 40, 42.
Key
6 — cdfgiko; 7 — acfghlmpqrtuvxya' e'; 24 — A automatic control, В application of control; 35— lb, 2c, 3a.
Power Plant Control System. Design
1. The system comprises the following units: basic unit, synchronizing and load sharing unit, additional monitoring unit, central units, relay unit, transformer unit, relay unit for controlled loads.
2. The electronic units consist of identical boxes furnished with different electronic boards and fronts. The boxes are made of sheet steel and provided with ventilation holes. A printed circuit board, the “mother board’’, constitutes the internal wiring and is connected to the terminal board by a flexible ribbon cable. Together, these two boards form the rear of the box. Some programming is performed by jumpers on the mother board.
The terminal board has two rows each with 33 terminals foe, external connections.
3. The electronic boards are inserted from the front of the box. All indi- >4 eating lamps and push-buttons are mounted on the boards and the front plate contains corresponding lamp glasses with engraved text.
4. The maximum number of different electronic boards is seven and every ' board has a distinct limitation of functions. This implies that any faults
can easily be corrected and few spare parts are required.
5. The relay and transformer units are built up in 19 inch standard racks and function as interface and output stages between the electronics and the peripheral equipment.
6. The basic units, the additional monitoring units and the central unit shall be applied from a 24 V battery, while the synchronizing and load sharing units are to be supplied from the generators via the transformer units.
7. The system can be adapted to different types of engines, generators and other relevant equipment.
1 7
Look through the text and write a summary about supply of power plant control system units.
2 3
Read the passages containing the information on:
a) boxes and boards of the electronic units (2);
b) the maximum number of different electronic boards and the reason for it (4);
c) application of the system (6).
Read the text paying attention to Participle II.
4 4
Repeat the words after the teacher. Then read them by yourself paying attention to their Russian equivalents.
relevant
5
Read the text carefully. Use ex. 4.
6
basic unit
synchronizing and load sharing unit
monitoring unit
relay unit for controlled loads
to furnish front
ventilation hole mother board terminal board flexible ribbon cable rear jumper lamp glass engraved text rack
as interface and output stage
— главный блок (устройство)
—блок (устройство) синхронизации и распределения нагрузки
— блок управления
— блок реле для контролируемых нагрузок
— снабжать
— передняя (панель)
— вентиляционное отверстие
— основная соединительная плата
— клеммная плата
— гибкий ленточный кабель
— задняя (панель)
— перемычка
— табло
— выгравированный текст
— стойка
— в качестве интерфейса (устройства сопряжения) и выходной ступени
- уместный, относящийся (к)
6 1
Read the words and point out those of the text:
a) design;
b) rear; c) plug;
