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Actions Overview
Here you will be introduced to the features and functionalities that are common to all MAVLink actions.
Action states
All actions have a common set of states that are used to provide information to the user. To explain each of these states the VTOL Takeoff action will be used as an example. "Command available" means that a command will be sent if the button is pressed.
| State | Display | Command available | Description |
|---|---|---|---|
| No link |  | ❌ | KH Control is not connected to a link. |
| No Data |  | ✅ | KH Control is connected to a link but no heartbeats have been received from the target in the last five seconds. |
| Connected |  | ✅ | KH Control is connected and receiving heartbeats from the vehicle. |
| Waiting for ACK |  | ❌ | A command has been sent, KH Control is waiting for the acknowledgment, this will timeout after five seconds if no acknowledgment is received. |
| ACK | see acknowledgment states | ✅ | Displaying received acknowledgment. |
Acknowledgment states
When in the ACK state the type of acknowledgment is displayed for a short time before returning to the underlying No link / No Data / Connected state.
| State | Display | Description |
|---|---|---|
| ACK OK |  | Acknowledgment received, result: Accepted or In progress. |
| ACK Fail |  | Acknowledgment received, result: Denied, Unsupported, Failed, Cancelled, Command long only, Command int only, unsupported altitude frame. |
| Timeout |  | No acknowledgment received after five seconds. |
| Send fail |  | Command could not be sent. |
| Configuration error |  | Error with action configuration, check action settings |
Active display
Some actions include feedback from the vehicle. When the vehicle is in the state that the action is configured for it will change in colour. There is also an unknown state where the state of the vehicle cannot be determined. An Arm/Disarm action configured to arm the vehicle is used as an example.
| State | Display | Description |
|---|---|---|
| Armed |  | The vehicle is armed. |
| Disarmed |  | The vehicle is disarmed. |
| Unknown |  | The armed/disarmed state of the vehicle is not known or has not been received for five seconds. |
Conventions
All actions follow some basic conventions to try and keep behaviour as consistent and predictable as possible.
Pressing a button triggers a single command, no matter the state of the vehicle. For example, Arm/Disarm could have been implemented as a toggle, however, this requires that KH Control knows the current state of the vehicle to know if arm or disarm command should be sent. If this state were to get out of sync for any reason the wrong command would be sent. This rule does mean that a separate action must be setup for arming and disarming. However, this removes unexpected results.
Pressing a button triggers exactly one command to be sent. There is no automatic retry. Again the goal of this is to remove unexpected behaviour and give the user complete control. The button state will show if no acknowledgement has been received and the user can then decide to retry manually.
Confirmation press
Actions can be configured to require a confirmation press. This can be used on critical actions to prevent accidental triggering. If enabled a new state is shown after the first press.
| State | Display | Description |
|---|---|---|
| Base state |  | State is displayed per Action states. Note the border is now an outline only, this allows actions which require a confirmation press to be easily identified. |
| Confirmation press |  | Awaiting confirmation press, if no second press happens in two and a half seconds the action returns to its base state. |
The confirmation press option can be found on at the top in the Command tab of the action settings.
TIP
Require a confirmation press on critical actions, such as force disarm.
Custom targets
The per-instance IDs option can be found in the advanced section of the Connection tab
If selected, each action will have user settable target component and system ID fields. This allows control of multiple vehicles or a vehicle and gimbal.
The target system ID and component ID will also be shown on the action itself. If no custom targets are entered the action will use the global settings. Target system ID is shown in the top left corner. Target component ID is shown in the top right corner. If the global target is set to auto system ID a question mark will be shown until the first system is detected.
| System ID | Component ID | Display |
|---|---|---|
| Auto | 1 |  |
| 42 | 1 |  |
TIP
Select a different colour palette for each custom target.