The standby command is executed after initialization and upon successful completion or cancellation of any other command. Commands that control the motor (e.g., drive or servo) will automatically cancel themselves, thereby triggering activation of the standby state, if no valid command was received in some configurable time interval referred to as the deadman timeout. This safety feature is intended to prevent uncontrolled operation of the drive in the event of an interface malfunction.

The fault state has to be reset (unlatched) by sending an explicit standby command.

Changes to the configuration parameters of any other command (e.g., drive) take effect when a state transition occurs from the standby command to the other command. For example, if the drive command parameters are changed while the motor is running, the changes will take effect after the motor is stopped and restarted again.


The standby command can be invoked via Cyphal by sending uavcan.node.ExecuteCommand with command code 0 (zero). Example using Yakut assuming node-ID 125:

1y cmd 125 0

Fault handling#

Since the standby command is needed to reset (unlatch) faults, it is also possible to issue it using the same interfaces that are used for controlling the motor (more on this in the respective sections).

  • The Cyphal interface will automatically issue a standby command if the current state is fault and the readiness state transitions from any other state to engaged, thus automatically resetting (unlatching) the fault state when the motor is started.

  • The auxiliary I/O interface will automatically issue a standby command if the current state is fault and the analog control signal enters the deadband zone.

Configuration registers#










See standby brake.

Standby brake#

If the standby brake voltage is set to a non-finite value (NaN) or a negative value, Telega will shut down the VSI hardware when executing the standby command, thereby allowing the rotor to freewheel. This is the default configuration.


If the motor is of the PMSM type and is spun by an external force sufficiently fast, such that the rectified back-EMF exceeds the DC link supply voltage, regeneration will still occur even with the standby brake disabled, resulting in some braking torque, due to the current rectification performed by the diodes in the VSI transistor bridge.

If the standby brake voltage is set to a finite non-negative value, Telega will keep the VSI enabled while in the standby state with the specified DC voltage applied at the motor phases. If the parameter is set to zero, this will effectively short the motor phase wires together. Any positive value will result in the torque aligning the rotor along the D-axis.

System status register#

This command is indicated via the system status register using the following schema.

{ "standby": UNSPECIFIED }

UNSPECIFIED may be replaced with an arbitrary value.