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4.2.2 Executing a multitask
Table 4-2:The multitask can be executed with the following three methods.
Types of execution
Execution from a program
1
2
Execution from controller
operation panel or external
input/output signa
3
Executing automatically
when the power is turned
on
4.2.3 Operation state of each slot
The operation state of each slot changes as shown in
Each state can be confirmed with the robot status variable or external output signal.
This method starts parallel operation of the programs from a random
position in the program using a MELFA-BASIC IV command. The pro-
grams to be run in parallel can be designated, and a program running in
parallel can be stopped.
This method is effective when selecting the programs to be run in paral-
lel according to the program flow.
The related commands include the XLoad, XRun, XStp and XRst com-
mands. Refer to
words"
in this manual for details.
In this execution type, depending on the setting of the information of the
"SLT*" parameter, the start operation starts concurrent execution or con-
stant concurrent execution, or starts concurrent execution at error occur-
rence. It is necessary to set the "SLT*" parameter in advance.
This method does not rely on the program flow, and is effective for carry-
ing out simultaneous execution with a preset format, or for sequential
execution.
It is possible to start constant execution immediately after turning the
controller's power on. If ALWAYS is specified for the start condition of
the SLT* parameter, the program is executed in constant execution
mode immediately after the controller's power is turned on.
This eliminates the trouble of starting the programs in task slots used for
monitoring input/output signals from the PLC side.
In addition, it is possible to execute a program from within another pro-
gram that controls movement continuously. In this case, set the value of
the "ALWENA" parameter to 7 in order to execute X** instructions such
as XRun and XLoad, the Servo instruction, and the Reset instruction.
selection state
Start
XRUN
Running
(RUN)
Fig.4-2:Operation state of each slot
Explanation
Page 152, "4.11 Detailed explanation of command
Fig. 4-2
according to the operations and commands.
Program
(PSA)
Cycle stop
Stop
XSTP
4MELFA-BASIC IV
Program reset
XRST
Waiting
(WAI)
Start
XRUN
Multitask function 4-118
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