Glossary
Glossary-9
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
The multipoint interface is the programming device interface in
SIMATIC S7/M7. It enables the simultaneous operation of a number of
nodes (programming devices, text display operator interfaces, and
operator panels) from one or more CPUs. Each node is identified by an
address (MPI address).
³ Multipoint Interface (MPI)
N
A block can be called from another block by means of block calls. The
nesting depth is the number of simultaneously called logic blocks.
In communications, a network is the connection between two or more
S7-400s/M7-400s and other terminals such as a programming device,
via a connecting cable. Data are exchanged over the network between
the connected stations.
The node number represents the accessing address of a CPU or
programming device or of another intelligent I/O module when they
communicate with each other via a network. The node number is
assigned by the CPU or programming device using the STEP 7
software.
In the case of non-isolated I/O modules, the reference potentials of the
control and load circuits are electrically connected to each other.
O
³ Organization Block
The operating system of the S7-400 CPU differentiates between
various priority classes, for example, cyclic program processing,
process interrupt-controlled program processing. Each priority class is
assigned organization blocks (OBs), where the S7 user can program a
reaction. As a standard, the OBs have different priorities to which they
are processed when they occur simultaneously or when they interrupt
each other.
Multipoint
Interface (MPI)
MPI Address
Nesting Depth
Network
Node Number
Non-Isolated
OB
OB Priority
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