Rockwell Automation 1794-APB/B FLEX I/O PROFIBUS Adapter Module User Manual - Manual (Page 87)

Chapter
3
Publication 1794ĆUM057B-EN-P - November 2001
Connect the Adapter to the
PROFIBUS DP Network
This chapter describes:
•
the DP physical layer
•
using line types A and B
•
equipment you need
•
how to connect the adapter to the network
•
how to terminate the network
The PROFIBUS network media is a balanced transmission line
corresponding to the standard EIA RS-485, terminated at both ends.
Both line A and line B types are available, depending on your system
requirements.
Specifications and guidelines for DP media:
•
linear bus, terminated at both ends
•
drop cables (preferably no longer than .30m), no branches
•
shielded twisted pair
•
max. line length between 100 and 1200m (depending on baudrate
and cable type)
•
number of stations: 32
•
DP baudrates: 9.6, 19.2, 93.75, 187.5, 500 Kbit/s and 1.5M bit/s
Use the following table to determine what line type will best meet
your needs.
Bus Segments and Drop Cables
Characteristic
Line A Requirements Line B Requirements
Total Capacity of
all Drop Cables
Impedance 135-165 W (3-29 MHz) 100-130 W (fu100 kHz)
Capacity t30 pF/m t60 pF/m
Resistance t110 W/km -
Wire Gauge u0.64 mm u0.53 mm
Conductor Area u0.34 mm 2 u0.22 mm 2
Maximum Length 1
v19.2k 1200 m 2 1200 m 2 v15nF
Maximum Length 1
with a Baud Rate
93.75k 1200 m 2 1200 m 2 v3nF
with a Baud Rate
(bits/s) of:
187.5k 1000 m 2 600 m 2 v1nF
(bits/s) of:
500k 400 m 2 200 m 2 v0.6nF
1.5M 200 m 2 NA v0.2nF
NA = Not Applicable
1
If using a combination of both line types, divide the lengths shown by two.
2
This is the sum of all bus segment and drop cable lengths.
What this Chapter Contains
The DP Physical Layer