Holding background task (from being activated)
The purpose of the background task is to monitor the status of the cell as a whole and to communicate with external devices. It is activated before a non-background task is activated and continues to function when the non-background task either generates an error or is aborted by an operator. In this sense, the background task can be a program that never stops functioning.
The background task can be debugged in PROGAM mode. By clicking the [Stop] button in the [Run] window, you can choose whether to abort the background task as well.
In the [Task Manager] window, the background tasks can be managed in the same way as the non-background tasks except for the [Pause/Cont] button. You can set a break point in a background task and step through the code.
As a rule, the background task cannot be controlled in AUTO mode. It is by design that any error that occurs in the background task cannot be recovered in AUTO mode. Therefore, thorough debugging in PROGRAM mode is recommended. Be particularly careful that the communication errors are handled properly without fail before using the background task in AUTO mode.
The following tables show how the background will (or will not) be affected by operation from the console.
Operator Window
| Button | Background task |
|---|---|
| Start | It will not be affected. |
| Abort | It will not be affected. |
| Pause | It will not be affected. |
| Continue | It will not be affected. |
Remote Input
| Button | Background task |
|---|---|
| Start / Stop | It will not be affected. |
| Pause / Continue | It will not be affected. |
| Reset | It will not be affected. |
| Shutdown | It will be stopped. |
Run Window (PROGRAM mode)
| Button | Background task |
|---|---|
| Start | You can select how to start the task. |
| Abort | You can select how to abort the task: abort only non-background task or abort all tasks including the background task. |
| Pause | It will not be affected. |
| Continue | It will not be affected. |
Task Manager (PROPGRAM mode)
| Button | Background task |
|---|---|
| Halt / Resume | When the background task is selected, you cannot execute Halt/Resume. |
| Quit | When the background task is selected, you can execute Quit. |
| Pause/Cont | It will not be affected. |
| Stop | All tasks including the background task will stop. |
Break point (PROGRAM mode)
| Switch name | Background task |
|---|---|
| Set a break point | You can set a breakpoint to the background task. It will pause at the break point. |
| Step Into | Available |
| Step Over | Available |
| Continue | Available |
| Walk | Available However, motion commands cannot be executed from background tasks. |