Touch screens displacing keypads
There is a continuing shift toward greater use of touch screens instead of keypads as input devices for operator interface terminals.
VDC cites several reasons for this upswing. Touch screens provide an easy-to-use graphic interface for data or command inputs and occupy less space than a keyboard. The incorporation of a small keypad or shortcut keys with a touch screen increases the usability of the operator interface terminal, and vendors are introducing such products.
Current market shares of industrial electronic operator interface terminal shipments in percent of dollar volume indicates that units with touch screens hold 53.8%, those with keypads occupy 29.8%, while terminals with both have 16.4%, according to VDC. The 2006 market shares are projected to be those with touch screens 56.3%, keypads 26.2%, and both 17.5%
Resistive technology accounts for the vast majority of touch screen shipments because of the cost-effectiveness and reliability of the technology. Capacitive touch screens have gained some market share since 2000 and many suppliers offer both. Capacitive touch screens are highly durable, but are more expensive than resistive units and cannot be used with gloves. Other technologies, such as near-field imaging, infrared, surface acoustic wave, and guided acoustic wave are used in some terminals, but are generally less capable of surviving harsh environments, or are too costly.