Precautions to Use the Special Tasks
CAUTION
Forced Flag
Specify Forced flags in I/O output commands such as On or Off to enable On/Off of I/O outputs at the following times:
During emergency stop, when safety door is open, in teach mode, or when an error occurs
Do not connect external equipment that operates mechanically such as actuator to the I/O output that specifies Forced flag. Doing so may cause external equipment to operate at the following times, which can be extremely dangerous:
During emergency stop, when safety door is open, in teach mode, or when an error occurs
Forced flag is designed to be specified for I/O outputs connected to external equipment without mechanical motion such as status display LEDs.
NoEmgAbort Task
When Emergency Stop or errors occur, finish the task promptly after completing the error handling.
If you do not complete the NoEmgAbort task, the controller does not change to Ready status and you cannot cancel the Emergency Stop or the error. You cannot execute Reset command from the NoEmgAbort task to cancel the Emergency Stop or the error automatically.
NoEmgAbort task is designed for I/O process without motion and communication with external device using the Ethernet. Therefore there are commands such as robot motion commands that cannot be executed in the NoEmgAbort task. An error occurs if you use these commands. The list of these commands is in the next section.
For details, refer to Help or the following manual:
"SPEL+ Language Reference - Xqt"
NoPause Task
NoPause task continues the operation during the Pause or Safety Door open condition. However, when a robot is operating NoPause task, the task pauses as the robot pauses.
Background task
Background task always exists while the controller is working, and it is designed for monitor of the entire system and communication with external device. Therefore there are commands such as robot motion commands that cannot be executed in the background task. An error occurs if you use these commands. The list of these commands is in the next section.
In addition, the background task continues processing even when Pause is input or safeguard is open, so it doesn't affect the controller state transition.
See details below.
[Outputs off during emergency stop] setting
Uncheck the [Outputs off during emergency stop] checkbox in the [Preferences] page of [Setup]-[System Configuration]-[Controller] to execute I/O On/Off using the NoEmgAbort task or background task after Emergency Stop. If this checkbox is checked, the execution order of turn Off by the controller and turn On using the task are not guaranteed.
[Safeguard open stops all tasks] setting
When the [Outputs off during emergency stop] checkbox in the [Preferences] page of [Setup]-[System Configuration]-[Controller] is checked, NoPause task stops by Safety Door open. NoEmgAbort task or background task continues the task.
Setting of [Enable the Background task]
Check the [Enable background tasks] checkbox in the [Preferences] page of [Setup]-[System Configuration]-[Controller] when you use the background task.
Setting of [Initialize global variables when function starts]
Uncheck the [Clear globals when MainXX function started] checkbox in the [Preferences] page of [Setup]-[System Configuration]-[Controller] when you use the global variables from the background task. When this checkbox is checked, the controller will initialize the variables and the variable-access conflict from tasks will occur.
CAUTION
Setting of [Enable advanced task commands]
Check the [Enable advanced task commands] checkbox in the [Preferences] page of [Setup]-[System Configuration]-[Controller] when you execute the following commands from a background task:
StartMain, Cont, Recover, Reset Error, Reset
When you execute these commands from a task, you should understand each command specification and verify that the system has the appropriate conditions. Note that improper use, such as executing commands continuously in a loop, can reduce the security of system.