Network Hardware User's Manual

TIWAY I Overview
1-5
SIMATIC TIWAY I Series 500 NIM User Manual
TIWAY I provides a Universal Command Language for all communication
on the network. The UCL consists of a set of high-level request/response
transactions known as Primitives. Primitives are used for:
• Reading and writing data
• Acquiring status of devices attached to the network
• Performing control operations on attached devices
Host Systems (computers or other intelligent devices) issue requests
(Primitives) to Network Interface Modules and Secondary Adapters. The
secondary interfaces then perform the requested operation on their attached
device and return the appropriate response to the Host Devices to complete
the transaction. (See Figure 1-1.)
The Series 500 NIM is the TIWAY I Network Interface Module for the
Siemens Series 500 Programmable Controllers. See Chapter 3 for a specific
listing of controllers supported by the Series 500 NIM.
The Series 500 NIM, which occupies two slots of a Series 500 I/O base,
provides redundant TIWAY I communication ports. Each of the following
models supports a specific type of network communication media.
Part Number Port A Port B
PPX:500–5039 Local Line Local Line
PPX:500–5040 RS-232-C/423 RS-232-C/423
The RS-232-C/423 media interface is configured as Data Terminal
Equipment (DTE) and is used to connect the NIM to Data Communication
Equipment (DCE) for operation with modems. This interface uses RS-423
drivers and receivers and operates at RS-423-A signal levels (+5 or –5 volts;
these levels are also RS-232-C compatible). The pin assignments for the
RS-232-C port are given in Table 2–1.
The Local Line interface is a differential line port for use with shielded
twisted pair cable. The Local Line interface provides line isolation and high
noise immunity for installations up to 10,000 feet (25,000 feet depending on
system loading and baud rate selection).
TIWAY I Universal
Command
Language, UCL
The Series 500 NIM