EtherCAT State Machine

The EtherCAT State Machine (ESM) is required on all EtherCAT devices. The ESM in general

defines 5 communication states of the slave device
- Init, Pre-Operational, Safe-Operational, Operational
- Bootstrap is an optional state for firmware upload
specifies initialization and error handling of the slave device
identifies the current communication relationship between the master and slave device
- requested and current state are accessed through the AL Control and AL Status registers

The ESM states can be transitioned as shown

Init State

No communication to the application layer is allowed
master only has communication to the data link registers (slave device eeprom, addressing, etc)

Pre-Operational State

Mailbox (SDO) communication to the application layer is available
No Process Data (PDO) communication.
PDO register mapping should be completed. Transition to Safe-Operation will configure mapping.

Safe-Operational State

Operational State

PDO Mappings

The Cool Muscle EtherCAT slave uses dynamic switching between modes and as such there is a single fixed PDO configuration.

The RxPDO is the PDO received by the motor/slave device

Object	Name	Units	Applicable Modes of Operation	Description
0x6040	Controlword	-	All	The Controlword is used to control the state of the mode of operation.
0x607A	Target position	pulses	CSP	Set the target position of the motor
0x60FF	Target speed	pulses/ms	CSV, PV	Set the target speed of the motor
0x60FE	Digital outputs	-	All	Set the state of the digital outputs
0x6060	Modes of operation	-	All	Set the required mode of operation

The TxPDO is the PDO transmitted by the motor/slave device

Object	Name	Units	Applicable Modes of Operation	Description
0x6041	Statusword	-	All	The Statusword describes the current state of the mode of operation.
0x6064	Position Actual Value	pulses	All	The value of the motor's actual position
0x606C	Speed Actual Value	pulses/ms	All	The value of the motor's actual speed
0x6077	Torque Actual Value	% rated torque	All	The value of the motor's actual peak torque
0x60FD	Digital Inputs	-	All	Digital inputs status
0x603F	Error	-	All	The actual error code currently active.
0x2301	Temperature	°c	All	The actual motor temperature in °c.
0x6079	DC Voltage	0.1VDC	All	The actual DC 24V DC bus voltage
0x6061	Modes of operation display	-	All	The mode of operation currently running.