[etherlab-users] Failed to calculate bus topology

[Graeme Foot]

Hi,

 

Get rid of the EL9010 terminator and use an EL9011 instead.  The EL9011
is cheaper and as far as I can tell the EL9010 is no longer listed.

 

In the meantime, just leave it off.  The EtherCAT terminals do not
require a terminator.  The EL9011 is just a cover to provide protection
for the exposed connectors.

 

 

The EL9010 opens the port of the terminal it is connected to, but it is
not actually a slave.  When the master is trying to calculate the
topology it iterates through the slaves looking for open ports and
assumes that if a port is open there is a slave connected to it.
Because there is no slave to communicate with when one is expected then
the iteration fails and the error is raised.

 

Important, if the topology can not be calculated then calculating the
propagation delays may also fail.  Valid propagation delays are required
for distributed clocks to be correct.

 

Regards,

Graeme.

 

________________________________

From: etherlab-users-bounces at etherlab.org
[mailto:etherlab-users-bounces at etherlab.org] On Behalf Of Steven
Hartmann
Sent: Thursday, 22 March 2012 10:08
To: etherlab-users at etherlab.org
Subject: [etherlab-users] Failed to calculate bus topology

 

Hi all,

I'm just getting started with the etherlab master stack, and really
ethercat in general, so please excuse my ignorance.  So far I have read
the documentation I have found (ethercat-1.5-***.pdf) as well was the
readme and install files, then I followed the directions to get the
driver installed.  I also cobbled together some beckhoff ethercat
modules including an EK1101, 3 EL2024s, and an EL2612 as well as an
EL9010 terminator.  I got everything startup up and an able to use the
command line tool to do a few queries to find that it sees all the
slices properly and can change the operational state.  One thing is
bothering me so far:  when I first plug in the ethercat modules I get
the following output in dmesg:

EtherCAT 0: Link state changed to UP.
EtherCAT 0: 6 slave(s) responding.
EtherCAT 0: Slave states: INIT.
EtherCAT 0: Scanning bus.
EtherCAT 0: Bus scanning completed in 440 ms.
EtherCAT ERROR 0: Failed to calculate bus topology.
EtherCAT 0: Slave states: PREOP.

I don't understand what the "Failed to calculate but topology" message
means, nor what I need to do to avoid it.  Any help would be
appreciated.

Thanks,

Steve

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