Filter
Top Products
Introduction
890USE19600 April 2004 11
What Is a Network Interface Module?
Purpose An island of STB I/O modules requires a network interface module (NIM) in the
leftmost location of the basic island. Physically, the NIM is the first (leftmost) module
on the island bus. Functionally, it is the gateway to the island bus—all
communications to and from the island bus pass through the NIM. The NIM also has
an integrated power supply that provides logic power to the island modules.
The Fieldbus
Network
An island bus is a node of distributed I/O on an open fieldbus network, and the NIM
is the island’s interface to that network. The NIM supports data transfers over the
fieldbus network between the island and the fieldbus master.
The physical design of the NIM makes it compatible with both an Advantys STB
island and your specific fieldbus master. Whereas the fieldbus connector on each
NIM type may differ, the location on the module front panel is essentially the same.
Other NIM connectors, such as the power supply interface, are identical for all NIM
types.
Communications
Roles The NIM manages the exchange of input and output data between the island and
the fieldbus master. Input data, stored in native island bus format, is converted to a
fieldbus-specific format that can be read by the fieldbus master. Output data written
to the NIM by the master is sent across the island bus to update the output modules
and is automatically reformatted.
Integrated Power
Supply
The NIM’s built-in 24-to-5 VDC power supply provides logic power to the I/O
modules on the basic segment of the island bus. The power supply requires a
24 VDC external power source. It converts the 24 VDC to 5 V of logic power,
providing 1.2 A of current to the island. Individual STB I/O modules in an island
segment generally draw a current load of between 50 and 90 mA. (Consult the
Advantys STB Hardware Components Reference Guide [890 USE 172] for a
particular module’s specifications.)
A basic NIM supports up to 12 Advantys STB I/O modules.