Siemens SIMATIC S7-400 Hardware And Installation Manual page 279

F
FB
FC
Flash EPROM With regard to their characteristic to retain data in the case of a power
failure, FEPROMs correspond to the electrically erasable EEPROMs,
but can be erased much faster (FEPROM = Flash Erasable
Programmable Read Only Memory). They are used on the memory
cards.
Function (FC) According to the International Electrotechnical Commission's IEC
1131-3 standard, functions are logic blocks that do not reference an
instance data block, meaning they do not have a "memory." A function
allows you to pass parameters in the user program, which means they
are suitable for programming complex functions that are required
frequently, for example, calculations.
Functional Grounding whose only purpose is to ensure the intended function of the
Grounding electrical equipment concerned. Functional grounding short-circuits any
noise that might otherwise have a detrimental effect on the equipment.
Function Block According to the International Electrotechnical Commission's
(FB) IEC 1131-3 standard, function blocks are logic blocks that reference an
instance data block, meaning they have static data. A function block
allows you to pass parameters in the user program, which means they
are suitable for programming complex functions that are required
frequently, for example, control systems, operating mode selection.
Function Module A programmable module which, in contrast to the CPU, has no
(FM)
multipoint interface and can only be operated as a slave.
G
GD Circle A GD circle comprises a number of CPUs which exchange data via
global data communication and are used as follows:
A GD circle is identified by a GD circle number.
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
www.gkbpx.com
Function Block
Function
A CPU sends a GD packet to the other CPUs.
A CPU sends and receives a GD packet from another CPU.
Glossary
Glossary-5