Rockwell Automation AADvance Controller Troubleshooting and Maintenance Manual - Manual (Page 93)

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Document: 553634
(ICSTT-RM406F_EN_P) Issue: 089:
8-9
Chapter 7 Glossary of Terms
SNCP
SNCP (Safety Network Control Protocol) is
the Safety Protocol that allows elements of
an AADvance System to exchange data.
SNCP is a SIL 3 certified protocol which
provides a safety layer for the Ethernet
network making it a "Black Channel".
SNTP
Simple Network Time Protocol. Used for
synchronizing the clocks of computer
systems over packet-switched, variable-
latency data networks.
structured text
A high level IEC 61131-3 language with
syntax similar to Pascal. Used mainly to
implement complex procedures that cannot
be expressed easily with graphical languages.
synchronous
A data communications term describing a
serial transmission protocol. A pre-arranged
number of bits is expected to be sent across
a line per second. To synchronise the
sending and receiving machines, a clocking
signal is sent by the transmitting computer.
There are no start or stop bits.
T
TA
See 'termination assembly'.
target
An attribute of a 'configuration' which
describes characteristics of the AADvance
controller on which the configuration will
run. Includes characteristics such as the
memory model and the sizes of variable
types for the controller.
TCP
Transmission control protocol. One of the
core protocols of the Internet Protocol
suite. It provides reliable, ordered delivery
of a stream of bytes from a program on one
computer to another program on another
computer. Common applications include the
World Wide Web, e-mail and file transfer
and, for an AADvance controller, Modbus
communications over Ethernet.
termination assembly
A printed circuit board which connects field
wiring to an input or output module. The
circuit includes fuses for field circuits. The
board carries screw terminals to connect
field wiring to the controller, and the whole
assembly clips onto the 9300 I/O base unit.
TMR
Triple modular redundant. A fault tolerant
arrangement in which three systems carry
out a process and their result is processed
by a voting system to produce a single
output.
TÜV certification
Independent third party certification against
a defined range of international standards
including IEC 61508.
U
U
Rack unit. A unit of measure used to
describe the height of equipment intended
for mounting in a standard rack. Equivalent
to 44.45mm (1-¾ inches).
V
validation
In quality assurance, confirmation that the
product does what the user requires.
verification
In quality assurance, confirmation that the
product conforms to the specifications.