Technical information
66
Composition
Modicon STB distributed I/O
solution
Open and modular system
Composition of a Modicon STB island
A Modicon STB island is made up of one or more segments comprising PDM power
distribution modules and I/O modules.
An island starts with a NIM network interface module and ends with a bus terminator
supplied with the NIM module.
An island can be made up of a single segment or a primary segment and up to
6 expansion segments.
The island segments are chained by EOS (End Of Segment) and BOS (Beginning Of
Segment) internal bus expansion modules. See page 9.
On each segment:
The PDMs must be placed immediately to the right of the network interface
modules or expansion modules.
The I/O modules are placed to the right of the PDM module supplying them with
power.
Each module (with the exception of the NIM network interface module) is held in a
xing base on the DIN rail
Three module and base widths are possible. On the DIN rail, the overall width
needed for a segment is the sum of widths of the network interface module, the
bases and any bus termination.
The bases ensure the continuity of the internal bus, the auto-addressing of the
modules, and the separated and isolated distribution of the internal power supplies,
actuators (outputs) and sensors (inputs).
The advantages of this arrangement are:
Unplugging modules:
When switched off (cold swap), all modules can be unplugged very quickly.
When switched on (hot swap), I/O modules can be unplugged provided the
network interface module is the standard type.
Output power supply independent of inputs: For example, if an output power
supply is cut by a Preventa module, the inputs are still managed.
Immunity of inputs: For example, the closing of power contactors (controlled by
outputs) does not disturb analog input measurements.
NIM network interface module:
This module manages communications on the island bus. It acts as a gateway for
exchanges with the eldbus or network master.
Different NIM interface modules (standard type only) are available for the following
main eldbuses or local area networks:
Ethernet Modbus TCP/IP: single port or double port NIM modules.
EtherNet/IP, InterBus, CANopen, Modbus Plus, Fipio, Probus DP and
DeviceNet.