Galil DMC-3425 user manual Example Command Error w/Multitasking

EN	End main program
#CMDERR	Command error utility
JP#DONE,_ED<>2	Check if error on line 2
JP#DONE,_TC<>6	Check if out of range
MG "SPEED TOO HIGH"	Send message
MG "TRY AGAIN"	Send message
ZS1	Adjust stack
JP #BEGIN	Return to main program
#DONE	End program if other error
ZS0	Zero stack
EN	End program

OPERAND	FUNCTION
_ED1	Returns the number of the thread that generated an error
_ED2	Retry failed command (operand contains the location of the failed command)
_ED3	Skip failed command (operand contains the location of the command after the
	failed command)

The operands are used with the XQ command in the following format: XQ _ED2 (or _ED3),_ED1,1

Where the “,1” at the end of the command line indicates a restart; therefore, the existing program stack will not e removed when the above format executes.

The following example shows an error correction routine that uses the operands.

Example - Command Error w/Multitasking

The following program illustrates a common program problem. In this case, a variable is used as a command argument and the variable is inadvertently set to an illegal value. This simple command error subroutine recognizes the type of error, modifies the variable and continues the program at the point of the error. If the program has an invalid command error, skip the command and continue to execute the program. To demonstrate the program, while the simple loop #A is executing on thread 0 (XQ#A,0), begin execution of the second task, XQ#B,1

Instruction	Interpretation
#A	Begin thread 0 (continuous loop)
JP#A
EN	End of thread 0
#B	Begin thread 1
KP -1	Set KP to value of N, an invalid value
TY	Issue invalid command
EN	End of thread 1
#CMDERR	Begin command error subroutine
IF(_TC=6)	If error is “Number Out of Range” (-1).
N=1	Set N to a valid number
XQ _ED2,_ED1,1	Retry KP N command
ENDIF
IF( _TC=1)	If error is “Invalid Command” (TY)

126 • Chapter 7 Application Programming DMC-3425