
Glossary
Glossary-5
ET 200S IM 151-7 CPU Interface Module
A5E00058783-04
ET 200
The ET 200 distributed I/O system with the PROFIBUS-DP protocol is a bus for
connecting distributed I/O devices to a CPU or an appropriate DP master. ET
200 is characterized by a rapid response time, since only a small amount of data
(bytes) is transmitted.
ET 200 is based on IEC 61784-1:2002 Ed1 CP 3/1.
The ET 200 works on the master/slave principle. Examples of DP masters are
the IM 308-C master interface module and the CPU 315-2 DP.
DP slaves can be the distributed I/O devices ET 200S, ET 200B, ET 200C,
ET 200M, ET 200X, ET 200U, ET 200L or DP slaves from Siemens or other
vendors.
FC Function
FORCE
During commissioning, for example, the “Force” function allows certain outputs to
be set to “ON” for any length of time, even if the logic operations of the user
program are not fulfilled (e.g. because inputs are not wired).
FREEZE
FREEZE is a control command of the DP master to a group of DP slaves.
After the FREEZE control command is received, the DP slave freezes the
current state of the inputs and transmits it cyclically to the DP master.
After each new FREEZE control command, the DP slave once again freezes the
state of the inputs.
The input data is transmitted cyclically again from the DP slave to the DP master
only after the DP master has sent the UNFREEZE control command.
Function
A function (FC) is, according to IEC 61131-3, a code block without statistical
data. A function allows the transmission of parameters in the user program.
Thus, functions are ideal for programming frequently recurring complex
functions, such as calculations.
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