[etherlab-dev] Multiple mailbox protocols and other issues

[Gavin Lambert]

On 3 February 2015 13:38, quoth Graeme Foot:
> Sent: Tuesday, 3 February 2015 13:38
> To: Gavin Lambert; 'Knud Baastrup'
> Cc: etherlab-dev at etherlab.org
> Subject: RE: [etherlab-dev] Multiple mailbox protocols and other issues
> 
> From: etherlab-dev [mailto:etherlab-dev-bounces at etherlab.org] On Behalf Of
> Gavin Lambert
> > On 2 February 2015 20:18, quoth Knud Baastrup:
> > > 16_improved_ethercat_rescan_performance.patch:
> > > The SII data and PDOs will now be stored when the EtherCAT master is
> > > in
> > its
> > > operation phase. The stored SII data and PDOs will be detached from
> > > the slaves prior to a scanning and re-attached during the scanning
> > > without the need to fetch the SII data and PDOs once again. The SII
> > > data and PDOs will however only be stored if the slave have a serial
> > > number defined as this serial number will be used when re-attaching
the
> SII data and PDOs.
> >
> > Ooh, thanks for that one.  That's one of the performance holes that I
was
> planning on investigating myself soonish.
> >
> 
> None of my modules seem to have serial numbers (Beckhoff IO and yaskawa
> amps), or is that a bug that's got a patch?  I'm running the original
1.5.2
> (+ misc patches).

It's not a bug, or really related to the master software at all.

It's up to the device manufacturer whether a given device has a serial
number or not.  In my case they do, but I'm mostly using in-house hardware.
Beckhoff modules as a general rule don't seem to have serial numbers.

This is separate from the "alias" which is used in network addressing and is
typically (but optionally) set by the network designer via the master
configurator.  The EtherLab master lacks specific commands to set aliases
but it can recognise aliases set by other masters, and some slaves support a
CoE download to reconfigure their alias (which can be accessed via the
command line), and some others have dipswitches.  Generally aliases are only
needed at "tree points" in the network graph, so if you're only using simple
chains they're less useful.

Technically the serial number can be altered by the master / network
designer as well via an EEPROM download, but this is less "encouraged".