Galil DMC-3425 user manual Debugging Programs

The main thread differs from the others in the following ways:

1.Only the main thread, thread 0, may use the input command, IN.

2.When automatic subroutines are implemented for limit switches, position errors or command errors, they are executed in thread 0.

To begin execution of the various programs, use the following instruction: XQ #A, n

Where n indicates the thread number. To halt the execution of any thread, use the instruction HX n

where n is the thread number.

Note that both the XQ and HX commands can be performed by an executing program. The example below produces a waveform on Output 1 independent of a move.

Instruction	Interpretation
#TASK1	Task1 label
AT0	Initialize reference time
CB1	Clear Output 1
#LOOP1	Loop1 label
AT 10	Wait 10 msec from reference time
SB1	Set Output 1
AT –40	Wait 40 msec from reference, then initialize reference
CB1	Clear Output 1
JP #LOOP1	Repeat Loop1
#TASK0	Task2 label
XQ #TASK1,1	Execute Task1
#LOOP2	Loop2 label
PR 1000	Define relative distance
BGA	Begin motion
AMA	After motion done
WT 10	Wait 10 msec
JP #LOOP2,@IN[2]=1	Repeat motion unless Input 2 is low
HX	Halt all tasks
EN	End of Program

The program above is executed with the instruction XQ #TASK0,0 which designates TASK0 as the main thread (i.e. Thread 0). #TASK1 is executed within TASK0.

Debugging Programs

The DMC-3425 provides commands and operands that are useful in debugging application programs. These commands include interrogation commands to monitor program execution, determine the state of the controller and the contents of the controllers program, array, and variable space. Operands also contain important status information that can help to debug a program. Breakpoint and single stepping commands are available to actively debug a program while in operation.

112 • Chapter 7 Application Programming DMC-3425