Installation / Preparation for commissioning
TR-Electronic GmbH 2011, All Rights Reserved
Printed in the Federal Republic of Germany
Page 96 of 139
TR - ELE - BA - DGB - 0022 - 04
02/08/2016
6.4 PROFIBUS-DP interface
6.4.1 RS485 Data transmission technology
All devices are connected in a bus structure (line). Up to 32 subscribers (master or
slaves) can be connected together in a segment.
The bus is terminated with an active bus termination at the beginning and end of each
segment. For stable operation, it must be ensured that both bus terminations are
always supplied with voltage. The bus termination can be switched on about a screw
plug in the upper part of the laser housing.
Repeaters (signal amplifiers) have to be used with more than 32 subscribers or to
expand the network scope in order to connect the various bus segments.
All cables used must conform with the PROFIBUS specification for the following
copper data wire parameters:
Parameter
Cable type A
Wave impedance in
135...165 at a frequency of 3...20 MHz
Operating capacitance (pF/m)
30
Loop resistance (
/km)
110
Wire diameter (mm)
> 0.64
Wire cross-section (mm²)
> 0.34
The PROFIBUS transmission speed may be set between 9.6 kbit/s and 12 Mbit/s and
is automatically recognized by the laser. It is selected for all devices on the bus at the
time of commissioning the system.
The range is dependent on the transmission speed for cable type A:
Baud rate (kbits/s)
9.6
19.2
93.75
187.5
500
1500
12000
Range / Segment
1200 m
1200 m
1200 m
1000 m
400 m
200 m
100 m
A shielded data cable must be used to achieve high electromagnetic interference
stability. The shielding should be connected with low resistance to protective ground
using large shield clips at both ends. It is also important that the data line is routed
separate from current carrying cables if at all possible. At data speed
1.5 Mbit/s,
drop lines should be avoided under all circumstances.
About the connector plugs in the upper part of the laser housing the inward and
outward data cables can be connected separately. This avoids drop lines.
The PROFIBUS guidelines and other applicable standards and guidelines are
to be observed to insure safe and stable operation!
In particular, the applicable EMC directive and the shielding and grounding
guidelines must be observed!
