Network Design Considerations
2-6 SIMATIC TIWAY I Series 500 NIM User Manual
2.3 Local Line Cable Installation
The following paragraphs describe Local Line characteristics and
installation guidelines.
The TIWAY I Local Line is a physical signaling technique (baseband,
differential current drive) which operates over shielded, twisted-pair
cabling. The Local Line cable may be up to 25,000 feet long, depending on
loading and baud rate selection. It uses tap housings to simplify the
addition of connections to TIWAY I. The Local Line is designed to operate
with shielded, twisted-pair cable which has a characteristic impedance of
124 ohms.
The interface is a male, 9-pin D-type receptacle with pin assignments as
shown in Table 2-2.
Table 2-2 Pin Assignments of Local Line Connectors
Pin Name Description
1No connection
2No connection
3 Shield Cable shield and signal common
4No connection
5No connection
6 LLM+ Positive biased signal line
7No connection
8No connection
9 LLM–Negative based signal line
NOTE: If you need Local Line cable redundancy, you will need one
PPX:500–5039 NIM, two separate twisted pair cables, and a T-Tap and
dropline for each port on the NIM. All taps and connectors are supplied with
the Local Line, but extras may be necessary for cable splicing. Suggested
routing procedures for redundant Local Line cabling are listed later in this
section.
Local Line
Characteristics