Electronic data boards consist of a rectangular plate that represents the surface of the screen. Some form of electric field is created over the plate. When a sensor is run over the board’s surface, it ‘senses’ the position of the sensor on the board. One common form of board is placed directly onto the screen, and in this case functions very like a light pen or touch screen. Another form of board is placed beside the screen, and one can work with a transparency of a picture. One of the advantages of the electronic data board is that one can very quickly make drawings or change them.
5.5.2 Voice Identihcation Instruments
Instruments for voice recognition and identification have been connected to computers for some time. Recognition of speech, however, is much more difficult (see Section 3.6). There are many apparent advantages of this type of device. It is, for example, very flexible and demands no special motor skill from the human operator. The problems are that the equipment available today requires specially trained operators who have to use a limited vocabulary and have to speak at a particular speed. In the future, however, this type of control may well be more widely applicable. Its present-day applications are primarily for different forms of emergency and alarm situations. There are many interesting possibilities for this form of control device within the process industries. Development should progress in such a way that natural words and sentences will be able to be used directly. In an emergency situation that requires immediate response, the operator should be able to shout ‘Stop’ to control the process if he or she considers this the appropriate action for the situation.
