fcat_msgs

Warning

This repository is deprecated. Please use nasa-jpl/fcat instead, which now includes fcat_msgs.

ROS 2 message and service definitions for the FCAT (Fieldbus Common Abstraction Tool) system.

Overview

This package defines 95 messages and 31 services used by the fcat node to interface with EtherCAT devices and software modules. Messages follow a consistent pattern:

• State/States - Telemetry published by fcat (e.g., ActuatorState, ActuatorStates)
• Cmd/Cmds - Commands subscribed to by fcat (e.g., ActuatorCspCmd, ActuatorCspCmds)
• Service - Request/response services exposed by fcat (e.g., ActuatorProfPosService)

States (plural) messages are variable-sized arrays of the corresponding singular State message. Similarly, Cmds (plural) messages wrap arrays of Cmd for multi-device commands.

Topic Namespacing

Prefix	Direction	Description
state/	fcat -> clients	Telemetry published every cycle
impl/	clients -> fcat	Low-level command topics (non-blocking)
cmd/	clients -> fcat	Service interface on the main fcat node
srv/	clients -> fcat	Blocking wrapper services on the fcat_srvs node

Messages

Actuator

Control and telemetry for EtherCAT servo drives.

Message	Topic	Description
ActuatorState	-	Single actuator telemetry
ActuatorStates	state/actuators	Array of actuator telemetry
ActuatorCspCmd / Cmds	impl/actuator_csp, impl/actuator_csp_multi	Cyclic Synchronous Position
ActuatorCsvCmd / Cmds	impl/actuator_csv, impl/actuator_csv_multi	Cyclic Synchronous Velocity
ActuatorCstCmd / Cmds	impl/actuator_cst, impl/actuator_cst_multi	Cyclic Synchronous Torque
ActuatorHaltCmd / Cmds	impl/actuator_halt, impl/actuator_halt_multi	Halt motion
ActuatorProfPosCmd / Cmds	impl/actuator_prof_pos, impl/actuator_prof_pos_multi	Profile Position mode
ActuatorProfTorqueCmd	impl/actuator_prof_torque	Profile Torque mode
ActuatorProfVelCmd	impl/actuator_prof_vel	Profile Velocity mode
ActuatorCalibrateCmd	impl/actuator_calibrate	Trigger calibration
ActuatorSetDigitalOutputCmd	impl/actuator_set_digital_output	Set digital output
ActuatorSetMaxCurrentCmd	impl/actuator_set_max_current	Set max current limit
ActuatorSetOutputPositionCmd	impl/actuator_set_output_position	Set output position
ActuatorSetProfDisengagingTimeoutCmd	impl/actuator_set_prof_disengaging_timeout	Set profile disengaging timeout
ActuatorSetUnitModeCmd	impl/actuator_set_unit_mode	Set unit mode

EGD (EtherCAT Gold Drive)

Message	Topic	Description
EgdState	-	Single EGD telemetry
EgdStates	state/egds	Array of EGD telemetry

Commander

Enable/disable device commanding.

Message	Topic	Description
CommanderState / States	state/commanders	Commander telemetry
CommanderEnableCmd	impl/commander_enable	Enable a commander
CommanderDisableCmd	impl/commander_disable	Disable a commander

Async SDO

Service Data Object read/write over EtherCAT.

Message	Topic	Description
AsyncSdoReadCmd	impl/async_sdo_read	Request an SDO read
AsyncSdoWriteCmd	impl/async_sdo_write	Request an SDO write
AsyncSdoResponse	state/async_sdo_response	SDO read/write response

EtherCAT I/O Terminals

State and command messages for Beckhoff EtherCAT terminals. Digital/analog output terminals include write commands; input-only terminals have state only.

Digital Input:

Message	Topic
El1008State / States	state/el1008s

Digital Output:

Terminal	State Topic	Commands
EL2124	state/el2124s	El2124WriteChannelCmd, El2124WriteAllChannelsCmd
EL2798	state/el2798s	El2798WriteChannelCmd, El2798WriteAllChannelsCmd
EL2809	state/el2809s	El2809WriteChannelCmd, El2809WriteAllChannelsCmd
EL2828	state/el2828s	El2828WriteChannelCmd, El2828WriteAllChannelsCmd

Analog Input:

Terminal	State Topic
EL3104	state/el3104s
EL3162	state/el3162s
EL3202	state/el3202s
EL3208	state/el3208s
EL3314	state/el3314s
EL3318	state/el3318s
EL3602	state/el3602s

Analog Output:

Terminal	State Topic	Commands
EL4102	state/el4102s	El4102WriteChannelCmd, El4102WriteAllChannelsCmd

Encoder:

Terminal	State Topic
EL5042	state/el5042s

Faulter

Message	Topic	Description
FaulterState / States	state/faulters	Faulter telemetry
FaulterEnableCmd	impl/faulter_enable	Enable a faulter

FTS (Force-Torque Sensor)

Message	Topic	Description
FtsState / States	state/fts	FTS telemetry
FtsTareCmd	impl/fts_tare	Tare a sensor

ILD1900 (Laser Displacement Sensor)

Message	Topic	Description
Ild1900State / States	state/ild1900s	Sensor telemetry

Signal Processing Modules

Message	Topic	Description
PidState / States	state/pids	PID controller telemetry
PidActivateCmd	impl/pid_activate	Activate/deactivate a PID
FilterState / States	state/filter	Filter telemetry
FunctionState / States	state/functions	Function telemetry
SaturationState / States	state/saturations	Saturation telemetry
SchmittTriggerState / States	state/schmitt_triggers	Schmitt trigger telemetry
SignalGeneratorState / States	state/signal_generators	Signal generator telemetry
LinearInterpolationState / States	state/linear_interpolators	Linear interpolation telemetry
ConditionalState / States	state/conditionals	Conditional telemetry
ThreeNodeThermalModelState / States	state/three_node_thermal_models	Thermal model telemetry

Other

Message	Topic	Description
ModuleState	state/module_state	Overall module state (always published)

Services

Actuator Services

Service	cmd/ topic	srv/ topic	Description
ActuatorCalibrateService	cmd/actuator_calibrate	srv/actuator_calibrate	Calibrate actuator
ActuatorHaltService	cmd/actuator_halt	-	Halt actuator
ActuatorProfPosService	cmd/actuator_prof_pos	srv/actuator_prof_pos	Profile position move
ActuatorProfTorqueService	cmd/actuator_prof_torque	srv/actuator_prof_torque	Profile torque move
ActuatorProfVelService	cmd/actuator_prof_vel	srv/actuator_prof_vel	Profile velocity move
ActuatorSetDigitalOutputService	cmd/actuator_set_digital_output	-	Set digital output
ActuatorSetGainSchedulingIndexService	cmd/actuator_set_gain_scheduling_index	-	Set gain scheduling index
ActuatorSetGainSchedulingModeService	-	srv/actuator_set_gain_scheduling_mode	Set gain scheduling mode (via TLC)
ActuatorSetMaxCurrentService	cmd/actuator_set_max_current	-	Set max current
ActuatorSetOutputPositionService	cmd/actuator_set_output_position	-	Set output position
ActuatorSetProfDisengagingTimeoutService	cmd/actuator_set_prof_disengaging_timeout	-	Set profile disengaging timeout
ActuatorSetUnitModeService	-	srv/actuator_set_unit_mode	Set unit mode (via TLC)

Other Services

Service	cmd/ topic	srv/ topic	Description
CommanderEnableService	cmd/commander_enable	-	Enable commander
CommanderDisableService	cmd/commander_disable	-	Disable commander
FaulterEnableService	cmd/faulter_enable	-	Enable faulter
PidActivateService	cmd/pid_activate	srv/pid_activate	Activate PID
DeviceTriggerService	cmd/fts_tare	-	Trigger device action (used for FTS tare)
AsyncSdoReadService	-	srv/async_sdo_read	Blocking SDO read
AsyncSdoWriteService	-	srv/async_sdo_write	Blocking SDO write
TlcReadService	-	srv/tlc_read	Two-Letter Command read
TlcWriteService	-	srv/tlc_write	Two-Letter Command write

EtherCAT I/O Services

Each writable terminal exposes both single-channel and all-channel services under cmd/:

Terminal	WriteChannelService	WriteAllChannelsService
EL2124	cmd/el2124_write_channel	cmd/el2124_write_all_channels
EL2798	cmd/el2798_write_channel	cmd/el2798_write_all_channels
EL2809	cmd/el2809_write_channel	cmd/el2809_write_all_channels
EL2828	cmd/el2828_write_channel	cmd/el2828_write_all_channels
EL4102	cmd/el4102_write_channel	cmd/el4102_write_all_channels