Control Techniques Nidec SI-EtherCAT User Manual page 60

The mode_of_operation object is read in all CiA402 states so that the operating mode can be
changed at any time, which is necessary for homing: some axes (e.g. vertical axes) have to be
homed and start ordinary positioning operation without the need to remove power from the motor,
which, on a vertical axis, might allow a tool, to fall and be damaged or cause damage. However, the
state machine will not perform a mode change until the motor is at zero speed, as far as can be
determined.
The max_motor_speed object specifies a maximum speed in rpm; it will have a default value
matching the drive parameter Pr 01.006 ("Maximum reference clamp", the object value will be set
to the value of Pr 01.006 at power up, or if Pr 01.006 is explicitly changed), and it will be used to set
this parameter. It will also be scaled and used to set the position controller output speed clamp
(Pr 39.011). It will be applied in all of the CiA402 operating modes. For example, if the
max_motor_speed object is set to 6000, the position controller output speed clamp will be set to a
value to give a limit of 6000 rpm.
The initial value of gear_ratio, feed_constant and additional_position_loop_scaling objects
(e.g. user configuration in start-up list) will be checked during the EtherCAT operational state
transition 'READY TO SWITCH ON' to 'SWITCHED ON'. During earlier CiA402 state machine
transitions, the value of these objects can be changed at any time. However the change won't take
effect until a CiA402 state transition from 'READY TO SWITCH ON' to 'SWITCHED ON' happens.
If any ratio fails to be applied, the EtherCAT module will not apply new values to the AMC.
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SI-EtherCAT User Guide