ifm
System Manual
ecomat
mobile
PDM360NG (CR1080, CR1081, CR9042) Target V01
2011-07-28
Glossary of Terms
457
System variable
Variable to which access can be made via IEC
address or symbol name from the PLC.
T
Target
The target indicates the target system where
the PLC program is to run. The target contains
the files (drivers and if available specific help
files) required for programming and parameter
setting.
TCP
The
T
ransmission
C
ontrol
P
rotocol is part of
the TCP/IP protocol family. Each TCP/IP data
connection has a transmitter and a receiver.
This principle is a connection-oriented data
transmission. In the TCP/IP protocol family the
TCP as the connection-oriented protocol
assumes the task of data protection, data flow
control and takes measures in the event of
data loss. (compare:
UDP)
Template
A template can be filled with content.
Here: A structure of pre-configured software
elements as basis for an application program.
Test rate rt
The test rate r
t
is the frequency of the
automatic tests to detect errors in an SRP/CS
in time.
U
UDP
UDP (
U
ser
D
atagram
P
rotocol) is a minimal
connectionless network protocol which belongs
to the transport layer of the internet protocol
family. The task of UDP is to ensure that data
which is transmitted via the internet is passed
to the right application.
At present network variables based on CAN
and UDP are implemented. The values of the
variables are automatically exchanged on the
basis of broadcast messages. In UDP they are
implemented as broadcast messages, in CAN
as PDOs. These services are not confirmed by
the protocol, i.e. it is not checked whether the
message is received. Exchange of network
variables corresponds to a "1 to n connection"
(1 transmitter to n receivers).
Uptime, mean
M
ean
T
ime
B
etween
F
ailures (MTBF)
Is the expected value of the operating time
between two consecutive failures of items that
are maintained.
NOTE: For items that are NOT maintained the
mean life
MTTF is the expected value (mean
value) of the distribution of lives.
Use, intended
Use of a product in accordance with the
information provided in the instructions for use.
W
Watchdog
In general the term watchdog is used for a
component of a system which watches the
function of other components. If a possible
malfunction is detected, this is either signalled
or suitable program branchings are activated.
The signal or branchings serve as a trigger for
other co-operating system components to
solve the problem.
wo
WO = write only
Unidirectional data transmission: Data can only
be changed and not read.