[etherlab-users] What are PDO index and subindex ?

[Florian Pose]

Hi nes,

On Sat, Nov 28, 2009 at 06:26:41PM +0900, Nesmis wrote:
> However, as I don't understand what "index" and "subindex" are
> in "ec_pdo_entry_info_t" structure. I cannot setup the
> "ec_pdo_entry_info_t" data. How can I get "index" and "subindex"
> from my slave board?
> And another question is, are these indices from CAN Open specification?

yes, but they are also defines in the EtherCAT specification.

> Since I didn't have any idea how to get these information, I used
> "ethercat" command tool with "reg_write" option to directly write
> parameters(SyncManager, FMMU settings, etc) to ESC registers.
> Then, I tried to write "0x08" to ALControl (0x120) to change AL status
> from PREOP to OP, but the ethercat driver said something like
> "slave not configured!".
> 
> How can I configure ethercat slaves without setting up "ec_pdo_entry_info_t"
> and calling "ecrt_slave_confgi_pdos()"?
> Is it possible in the first place?

Yes, have a look on the output of 'ethercat pdos' before starting your
application, then you will see the default PDOs/PDO entries your slave
provides. The ecrt_slave_config_pdos() function is necessary to
predefine the PDO layout. This has two reasons: To make the master know
the PDOs before the slave is connected, to calculate the process data
image before the bus is connected, or if you want to change the PDO
layout.

-- 
Best regards,
Florian Pose

http://etherlab.org