Introduction
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 |
| 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 |
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An island bus is a node of distributed I/O on an open fieldbus network, and the NIM | |
Network | 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 |
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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 |
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| to the NIM by the master is sent across the island bus to update the output modules |
| and is automatically reformatted. |
Integrated Power |
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The NIM’s | |
Supply | 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. |
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890USE19600 April 2004 | 11 |