Debugging Programs - Galil Motion Control DMC-18 2 Series User Manual

JP #LOOP2,@IN[2]=1
HX
The program above is executed with the instruction XQ #TASK2,0 which designates TASK2 as the
main thread (i.e. Thread 0). #TASK1 is executed within TASK2.

Debugging Programs

The DMC-18x2 provides commands and operands which are useful in debugging application
programs. These commands include breakpoint, single line step through, and 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 which can
help to debug a program.
Trace Commands
The trace command causes the controller to send each line in a program to the host computer
immediately prior to execution. Tracing is enabled with the command, TR1. TR0 turns the trace
function off. Note: When the trace function is enabled, the line numbers as well as the command line
will be displayed as each command line is executed.
Data which is output from the controller is stored in an output FIFO buffer. The output FIFO buffer
can store up to 512 characters of information. In normal operation, the controller places output into the
FIFO buffer. The software on the host computer monitors this buffer and reads information as needed.
When the trace mode is enabled, the controller will send information to the FIFO buffer at a very high
rate. In general, the FIFO will become full since the software is unable to read the information fast
enough. When the FIFO becomes full, program execution will be delayed until it is cleared. If the
user wants to avoid this delay, the command CW,1 can be given. This command causes the controller
to throw away the data which can not be placed into the FIFO. In this case, the controller does not
delay program execution.
Error Code Command
When there is a program error, the DMC-18x2 halts the program execution at the point where the error
occurs. To display the last line number of program execution, issue the command, MG _ED.
The user can obtain information about the type of error condition that occurred by using the command,
TC1. This command reports back a number and a text message which describes the error condition.
The command, TC0 or TC, will return the error code without the text message. For more information
about the command, TC, see the Command Reference.
Stop Code Command
The status of motion for each axis can be determined by using the stop code command, SC. This can
be useful when motion on an axis has stopped unexpectedly. The command SC will return a number
representing the motion status. See the command reference for further information.
RAM Memory Interrogation Commands
For debugging the status of the program memory, array memory, or variable memory, the DMC-18x2
has several useful commands. The command, DM ?, will return the number of array elements
currently available. The command, DA ?, will return the number of arrays which can be currently
defined. For example, a standard DMC-1812 will have a maximum of 8000 array elements in up to 30
arrays. If an array of 100 elements is defined, the command DM ? will return the value 7900 and the
command DA ? will return 29.
114 ● Chapter 7 Application Programming
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Repeat motion unless Input 2 is low
Halt all tasks
DMC-18x2