Siemens SIMATIC S7-400 Installation Manual page 217

Multipoint Interface (MPI)
The multipoint interface is the programming device interface in SIMATIC S7. 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
→ Multipoint Interface (MPI)
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 S7-400
CPUs 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.
Automation System S7-400 Hardware and Installation
A5E00850741-01
Glossary
Glossary-9