Hello all,
First of all thanks for the terrific stack, we've made really rapid progress
integrating EtherLab into our existing software.
For reference, our kernel is 4.14 using RT-PREEMPT, EtherLab is 1.5.2 with
Gavin's patches (cribbed from https://github.com/ribalda/ethercat). We are
using the ecrt library in user-mode.
We do have one remaining issue to iron out however. We are using Beckhoff
AX5000 servo drives (all single channel AX51xx-series) which are SoE devices.
After a serious (Sercos "class 1") fault (e.g. over-current, over-temperature
etc.) they require the fault to be acknowledged by writing to IDN S-0-0099.
This IDN cannot be mapped into process data, so must be written with an
explicit SoE write request.
S-0-0099 is listed as being changeable in PreOp, SafeOp and Op, and TwinCAT is
happy to write to it while running in Op. One can also trigger the same
fault-clearing functionality through the little LCD menu on the front-panel of
the drives, which works seamlessly while our cyclic task continues to run and
is even referred to in Beckhoff's docs as corresponding to S-0-0099. Of course
we will be hiding the drives away in a cabinet so we'd like to do it through
EtherLab.
The ecrt.h prototype documentation doesn't mention that a
ecrt_master_write_idn() *can't* be called from within the realtime context,
but testing this seems to indicate it shouldn't be called within the cyclic
task; we immediately lock up our loop. In any case, given
ecrt_master_write_idn() is blocking I don't think we want to call it in a
sensitive (=many DC slaves) loop.
Using the command-line tool to write the IDN while our realtime application
continues to run *mostly* works, although frequently the IDN either fails to
write, or sometimes even blocks the command-line tool entirely from returning
until our main application is terminated. Debug output from ethercat shows the
following repeating ad infinitum:
EtherCAT DEBUG 0-main-4: SSC write request:
EtherCAT DEBUG: 03 40 63 00 00 00
EtherCAT DEBUG 0-main-4: SSC write request:
EtherCAT DEBUG: 03 40 63 00 00 00
EtherCAT DEBUG 0-main-4: SSC write request:
EtherCAT DEBUG: 03 40 63 00 00 00
We have also tried calling the same ioctl in a separate thread (outside of our
cyclic task thread) to write to the IDN; this produces basically identical
results as the command-line tool (works 80% of the time, with occasional
lockups and need to reboot or at least restart the master).
Is there something we've missed? I feel if we could request a transition back
to Idle or PreOp this might be enough, maybe even using
ecrt_slave_config_idn() to write to S-0-0099 automatically. However there are
no knobs I can see to request a slave state change (at least from user-mode),
is this correct?
The nuclear option would be to restart all slaves by using
ecrt_master_deactivate() and then starting from scratch, but this seems
somewhat brutal if it's just a matter of writing an IDN.
Thanks once again,
Tom
_______________________________________________
etherlab-users mailing list
[email protected]
http://lists.etherlab.org/mailman/listinfo/etherlab-users
