Omron CJ1W-PRT21 Operation Manual page 42

Setting up a network
Fieldbus connector
3-3-2 Configuring PROFIBUS-DP systems
Configurator
The connector plug to be used on the CJ1W-PRT21 is a 9-pin male sub-D
connector, preferably with a metal case, and a facility to connect the shield of
the cable to the case. The cable should at least be connected to pin 3 (B-line)
and pin 8 (A-line) of the connector.
At baud rates of 1.5 Mbit/s or higher, always use special PROFIBUS-DP con-
nectors with built-in series inductances, to ensure that cable reflections
caused by the capacitive the load of each unit are minimised.
Connectors with built-in inductors and termination resistors, as shown here
schematically, are available from various manufacturers.
To ensure electromagnetic compatibility (EMC), the shield of the cable should
be connected to the metal case of the connector. If this is impossible, use pin
1.
When the Unit is installed within a control cabinet, the cable shield of the bus
cable should be electrically connected to a grounding rail as close as possible
to the cable lead-through using a shield grounding clamp or similar. The cable
shield should continue within the cabinet to the fieldbus device. Ensure that
the PLC and the control cabinet in which the device is mounted have the
same ground potential by providing a large-area metallic contact to ground
(use e.g. galvanised steel to ensure a good connection). Grounding rails
should not be attached to painted surfaces.
You may find further information about:
• Commissioning of PROFIBUS equipment
• Testing the PROFIBUS cable and bus connectors
• Determining the loop resistance
• Testing for correct bus termination
• Determining the segment length and cable route
• Other test methods
• Example of an equipment report
in the PROFIBUS guideline "Installation Guideline for PROFIBUS-DP/FMS"
(PNO Order No- 2.112), which is available at every regional PROFIBUS user
organisation.
After making the physical connections of the network, the PROFIBUS-DP
system needs to be configured. For each master and its assigned slaves, a
configuration has to be defined using a dedicated configuration program.
The configurator provides the master with information about:
• The slaves that are connected to the master.
• The assignment of slaves to groups for broadcast / multicast messages.
• The mapping of the slaves into the memory of the master.
• The bus parameters (e.g. baud rate, target rotation time etc.).
Section 3-3
23