Dear all,

Please first take a look at our attached configuration showing one of the ASs in
our system. This is a new commissioning with PCS7 V8.0 SP1 + Cemat V8.0.
System was not in operation once before!

Problem occurs in three different S7-400H plcs. That's why we are thinking,
that Profibus connections are OK. There must be a common problem.

Optical links between Rack0 and Rack1 are OK.

In our S7-400H configuration, We are using OLM-G22s to connect
redundant Profibus lines to I/O panels and other devices. OLMs
are adjusted as redundant ring. No matter if S7-400H is in
redundant mode or in solo mode, we have always BF1 by IM153s of ET200M and Y-Links. DP slaves can not be monitored in the Profibus lines.
In HW Configuraton, DP slaves are indicated as gray. Communication
can not be established. Even some of the devices (Siprotecs) can
be monitored as OK, signals are changing their status as flashing
bits. Some of the AI cards indicating faults and analog values can not be
read. By the upper OLMs (OLMs in the Plc panel), CH0 and CH1 are
not "ON" at the same time. When we switch off and on the OLM-G22, only CH0
or CH1 is "ON" by coincidence. When you switch off the rack, to which the
active electrical channel (for instance CH0) is connected, immediately the
other electrical channel (for instance CH1) becomes active.

When we switch off one Profibus line's IM153s (with single IM153
by all ET200Ms and Y-Links) all DP slaves can be monitored in HW
configuration as "OK" with black indication. No red markings.
Same happens with the other Profibus line's IM153s and Y-Links.
Communication is stable. Redf led is still on, but we want to solve first the
bus fault.

We tried the following for the Cpu DP interfaces:

In the Plc Panel:
==============

- Profibusconnections for OLM-G22 Nr.2 have been temporarilyremoved.
- Profibus line from Rack0 Cpu Dp is connected to CH0 of OLM-G22 Nr.1
- Profibus line from Rack1 Cpu Dp is connected to CH0 of OLM-G22 Nr.2

In the I/O Panel (on the other side of FOC):
==================================

- Profibusconnections for OLM-G22 Nr.2 have been temporarilyremoved.
- CH0 of OLM-G22 Nr.1 is connected to left IM153s
- CH0 of OLM-G22 Nr.2 is connected to right IM153s
- Left and right IM153s are energized by all ET200Ms and Y-Links.

Result in the Plc Panel:
===================

- CH0 leds of both OLM-G22s are "ON". (With one OLM-G22, CH0 and CH1 were not"ON" at the same time)

Result in the I/O Panel (on the other side of FOC):
=======================================

- CH0 leds of both OLM-G22s are "ON".
- There are no more "BF1" bus faults and all the DP Slaves are healthy.
- When we switch off the "ACT" IM153, ET200 or Y-Link switches to the other
IM153 and it becomes "ACT".

Results observed on Engineering Station:
==============================
- DP communication is stable.

Same happens, when we use CH1s of the OLM-G22s.

According to pressrelease of OLM-G22:
"The OLM P22 and OLM G22 modules each have two optical Profibus interfaces using bayonet fiber optic connector (BFOC) technology and two electrical interfaces of the sub-D type. This enables two separate electronic Profibus segments to be integrated into one optical network structure, such as a redundant ring"

http://www.siemens.com/press/en/pressrelease/?press=/en/pressrelease/2010/industry_automation/iia2010112603.htm

What can be the problem? What is the difference between using one OLM-G22 with all its channels and using two OLM-G22 partially.

Sorry for this longmessage. Any help will be highly appreciated.

Thanks in advance.
BC

Hi RIAN Che,

Sorry for late reply. In first configuration just add one OLM-G12 for each OLM-G22 and move the fiber and copper cables indicated as dotted lines on OLM-G22s to the OLM-G12s. Then it's the final configuration.

Best regards.

BC