[etherlab-users] how to get the absolute slave position from userspace ?

[Sebastien Blanchet]

Hi,

I am still facing a problem:

I would like to use ecrt_master_sdo_upload and ecrt_master_sdo_download
but I did not know how to get the absolute slave position (param #2)

ecrt.h says:

/** Executes an SDO download request to write data to a slave.
  *
  * This request is processed by the master state machine. This method blocks,
  * until the request has been processed and may not be called in realtime
  * context.
  *
  * \retval  0 Success.
  * \retval <0 Error code.
  */
int ecrt_master_sdo_download(
         ec_master_t *master, /**< EtherCAT master. */
         uint16_t slave_position, /**< Slave position. */
         uint16_t index, /**< Index of the SDO. */
         uint8_t subindex, /**< Subindex of the SDO. */
         uint8_t *data, /**< Data buffer to download. */
         size_t data_size, /**< Size of the data buffer. */
         uint32_t *abort_code /**< Abort code of the SDO download. */
         );


I have tried to iterate over slaves info with ecrt_master_get_slave() to fill 
ec_slave_info_t but indeed ec_slave_info_t contains the relative slave position 
when the slave alias is not null.

I have also studied the source code of the 'ethercat slaves' tool (in 
tool/CommandSlaves.cpp) but it uses functions that are not exported in ecrt.h

Finally, does someone have an idea ?

otherwise I will be forced to parse the output of 'ethercat slaves' to get 
absolute slave position. (very ugly)

best regards,
-- 
Sebastien BLANCHET