SIEMENS
3/143
Siemens IK PI · 2015
PROFIBUS
Optical networks with OBT and integrated interface
Optical bus terminal OBT
3
■
Overview
•
For connecting a PROFIBUS station without an integrated
fiber-optic cable interface or an RS 485 segment to an optical
line
•
Quick and easy installation of the plastic fiber-optic cable
without the need for special tools
■
Benefits
•
Option of connecting existing devices or an RS 485 segment
with electrical interface to the optical PROFIBUS
•
"Socket outlet" for connecting mobile devices (e.g.
programming devices) without interruption of the bus
•
Time saved through simple and fast connector mounting
without special tools
■
Application
The OBT (Optical Bus Terminal) is used to connect a PROFIBUS
station without integral optical interface or a PROFIBUS DP
RS485 segment to an optical line. Existing DP devices are then
provided with the advantages of optical data transmission.
The PROFIBUS station is connected to the RS 485 interface of
the OBT via a cable terminated at both ends, e.g. connecting
cable 830-1T. The OBT is integrated into the optical line using
two optical interfaces.
The following optical transmission media can be connected to
the OBT:
•
Plastic fiber-optic cables can be used up to an individual
segment length of 50 m. They can be configured very easily
on site with 2 x 2 Simplex connectors.
• PCF
1)
fiber-optic cables can be used for an individual
segment length up to 300 m. These cables are preassembled.
The OBT supports all PROFIBUS data transmission rates up to
12 Mbit/s.
1)
Also known as HCS
®
fiber-optic cable:
HCS
®
is a registered trademark of Lucent Technologies.
■
Design
The OBT has a compact plastic housing. It is suitable for
mounting on a DIN rail or for wall mounting with a mounting plate
with the aid of two holes drilled right through.
The OBT has the following connections:
•
9-pin sub-D socket for connecting the PROFIBUS DP node
such as programming device (PG), PC, operator panel (OP),
S7-300 or nodes without integral optics, e.g. ET 200S or
PROFIBUS DP components from other suppliers or a
PROFIBUS DP-RS 485 segment.
•
Two optical interfaces for the connection of plastic and PCF
fiber-optic cables with Simplex connectors (connection to
CP 342-5 FO, CP 5613 FO, IM 153-2 FO, IM 467 FO or to
ET 200 with integrated optics)
•
24 V DC infeed for power supply
■
Function
•
Connection of a station with RS 485 interface via connecting
cable 830-1T or PROFIBUS cable with bus connectors
(terminated at both ends) or an RS 485 segment
•
Provision of an electrical connection point on the optical line
(e.g. PG connection for startup and diagnostics).
•
Support for all PROFIBUS data rates from 9.6 kbit/s to
12 Mbit/s including 45.45 kbit/s for PROFIBUS PA
•
Regeneration of the signals in amplitude and time
•
Cascade depth when using user-defined bus parameters up
to 126 stations
•
Galvanic isolation of the station via fiber optic cable
•
Simple diagnostics via LED display for operating voltage as
well as for receipt of data CH1, CH2 and CH3.
© Siemens AG 2014