B&R Industries Provit 5000, User Manual

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374 Provit 5000 User’s Manual
Technical Appendix • Glossary
RTS
An abbreviation for »Request To Send« A signal used in serial data transfer for requesting send
permission. For example, it is sent from a computer to the modem connected to it. The RTS
signal is assigned according to hardware specifications of the RS-232-C standard for connection
4.
RXD
An abbreviation for »Receive (RX) Data« A line for the transfer of serial data received from one
device to another - e.g. from a modem to a computer. For connections complying with the RS-
232-C standard, the RXD is controlled by connection 3 of the plug.
SDRAM
An abbreviation for »Synchronous Dynamic Random Access Memory« A construction of
dynamic semiconductor components (DRAM), which can operate with higher clock rates than
conventional DRAM switching circuits. This is made possible using block access. For each
access, the DRAM determines the next memory addresses to be accessed.
Special Keypad Modules
The following keypad modules are offered by B&R: Dummy module, emergency stop module,
key switch module (made up of 1 key switch and 1 on /off switch) and a start/stop module (made
up of 2 buttons and a label field).
SRAM
An abbreviation for »Static Random Access Memory« A semiconductor memory (RAM) made
up of certain logic circuits (flip-flop), which only keeps stored information while the operating
voltage is active. In computers, static RAM is generally only used for the cache memory.
Standard Keypad Module
The following keypad modules are offered by B&R: 16 keys with 16 LEDs, 12+4 keys with 4
LEDs, 8 keys with 4 LEDs and a label field and 4 keys with 4 LEDs and 4 label fields.
SVGA
An abbreviation for »Super Video Graphics Array« A graphic standard which was created in
1989 by the Video Electronics Standards Association (VESA) in order to offer the option of high
resolution color screens for IBM compatible computers. Although SVGA is a single standard,
compatibility problems can occur with the video BIOS.