Listing EtherCAT Slaves and Actuator Roles#

list_ethercat_slaves is a command line utility, installed on the robot, that lists all the EtherCAT slaves detected on the bus together with their serial numbers. Optionally, it can also show the human-readable actuator role, the actuator type, the actuator serial number, and the firmware version of each slave. It is the quickest way to check that all the expected actuators are present on the bus and correctly identified before starting the robot.

Usage#

list_ethercat_slaves [OPTIONS]

Option	Description
`-a`, `--all`	Show all available columns (role, type, actuator serial, firmware version)
`-r`, `--role`	Include the actuator role in the output
`-t`, `--actuator-type`	Include the actuator type in the output
`-s`, `--actuator-serial`	Include the actuator serial number in the output
`-f`, `--firmware-version`	Include the firmware version in the output
`-h`, `--help`	Display the help message

Output columns#

Column	Description
`Num`	Slave number on the bus
`Pos`	Slave position, as `<alias>:<position>`
`State`	Current EtherCAT state of the slave (`OP`, `PREOP`, etc.). `PREOP` is expected for devices that are not actuators, such as the EtherCAT junctions
`Flag`	Status flag of the slave. `+` means the slave has no error flags set
`Device`	Device name reported by the slave (truncated to 20 characters)
`Serial`	Slave serial number, read from CoE object `0x1018:4`
`Role`	Human-readable actuator role name, read from CoE object `0x10E0:1` (shown with `-r`/`--role`) — see Actuator roles
`Type`	Actuator hardware type code, read from CoE object `0x1019:1` (shown with `-t`/`--actuator-type`) — see Actuator types
`Actuator SN`	Actuator serial number, read from CoE object `0x1019:2` (shown with `-s`/`--actuator-serial`)
`FW Version`	Firmware version string, read from CoE object `0x100A:0` (shown with `-f`/`--firmware-version`)

Columns that cannot be read for a given slave (for example, the EtherCAT junctions, which are not actuators) are reported as N/A.

Example#

Running the tool with all columns enabled on a Kangaroo without arms and without feet FT sensors gives an output similar to this:

$ list_ethercat_slaves -a
Num   Pos    State  Flag  Device                Serial           Role                            Type   Actuator SN      FW Version
----------------------------------------------------------------------------------------------------------------------------------------
   0:0    PREOP  +     GX-JC06(IN,X2,X3)     N/A              N/A                             N/A    N/A
   0:1    OP     +     mc21_f2838x_cm        7097576          leg_right_1_actuator            KA     80               1.22.1-0
   0:2    OP     +     mc21_f2838x_cm        7097719          leg_right_2_actuator            KA     78               1.22.1-0
   0:3    OP     +     mc21_f2838x_cm        7097558          leg_right_3_actuator            KA     77               1.22.1-0
   0:4    OP     +     mc21_f2838x_cm        7097711          leg_right_4_actuator            KA     72               1.22.1-0
   0:5    OP     +     mc21_f2838x_cm        7097720          leg_right_5_actuator            KA     74               1.22.1-0
   0:6    OP     +     mc21_f2838x_cm        11496239         leg_right_length_actuator       LL     7                1.22.1-0
   0:7    OP     +     mc21_f2838x_cm        7121395          leg_left_1_actuator             KA     73               1.22.1-0
   0:8    OP     +     mc21_f2838x_cm        7097595          leg_left_3_actuator             KA     76               1.22.1-0
   0:9    OP     +     mc21_f2838x_cm        7097586          leg_left_2_actuator             KA     75               1.22.1-0
  0:10   OP     +     mc21_f2838x_cm        7097580          leg_left_5_actuator             KA     71               1.22.1-0
  0:11   OP     +     mc21_f2838x_cm        7121369          leg_left_4_actuator             KA     79               1.22.1-0
  0:12   OP     +     mc21_f2838x_cm        11496236         leg_left_length_actuator        LL     8                1.22.1-0
  0:13   PREOP  +     GX-JC06(X4,X5,X6)     N/A              N/A                             N/A    N/A
  0:14   OP     +     mc21_f2838x_cm        6758610          pelvis_1_actuator               S+     991              1.22.1-0
  0:15   OP     +     mc21_f2838x_cm        8577867          pelvis_2_actuator               S+     1006             1.22.1-0

Slaves 0 and 13 are the two EtherCAT junctions (Omron GX-JC06) that create the star topology described in the Electronics Overview — they are not actuators, so they stay in PREOP state and report N/A for every actuator-specific column. All other slaves are mc21_f2838x_cm motor control boards, one per actuator, correctly identified by their role.

Actuator roles#

The role of a slave is a configuration value stored on the actuator itself (CoE object 0x10E0:1) and read out as a human-readable name by list_ethercat_slaves -r. It identifies the name of the actuators, independently of its EtherCAT slave position, which makes it possible to spot a wrongly cabled or a swapped actuator immediately. A slave that does not implement the role object (for example, the EtherCAT junctions) is reported as N/A.

Actuator types#

The Type column decodes the last two bytes of CoE object 0x1019:1 as ASCII, and identifies which of the three actuator module variants is mounted on that slave:

Type code	Actuator module
`KA`	Linear Actuator Module (hip and ankle joints)
`LL`	Leg Length Actuator Module (leg extension actuator)
`S+` / `S-`	SEA Rotary Actuator Module (pelvis and arm joints)

Listing EtherCAT Slaves and Actuator Roles

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