Siemens SIMATIC S7-400 Hardware And Installation Manual page 283

Multipoint The multipoint interface is the programming device interface in
Interface (MPI) 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).
MPI Address
N
Nesting Depth A block can be called from another block by means of block calls. The
nesting depth is the number of simultaneously called logic blocks.
Network 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.
Node Number 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.
Non-Isolated 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
OB
OB Priority 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.
S7-400 and M7-400 Programmable Controllers, Installation Manual
C79000-G7076-C424-01
www.gkbpx.com
Multipoint Interface (MPI)
Organization Block
Glossary
Glossary-9