Error Handling 06/2005 Danaher Motion
158 Rev E M-SS-005-03l
During the internal error action, the synchronous error is logged in the MC
and the task is idled. The default system error handler stops all motion and
all attached tasks.
In the figure above, there are two mechanisms for trapping and dealing with
errors: OnError and Try/Finally blocks. These two error-handling
mechanisms allow you to write your program to respond to errors.
11.1.1.1. ONERROR
The OnError block is handled like an event handler. An event handler lets
your program respond to events. The OnError block allows your program to
catch errors. OnError overrides default system error action if OnError traps
error. Main program execution is stopped while the OnError block is
executing and must be resumed if that is desired. An example of this is
shown later in this section.
Add an OnError code block to your program between the Program and End
Program section of your program.
The number of Catch statements in an OnError block is not explicitly limited.
Catch Else may optionally be used. If you want a task to resume after an
error has occurred, use CONTINUETASK.
You can use GoTo within the error handler. However, because OnError
interrupts the main program, you cannot use GoTo to branch outside the
error handler. You cannot place an OnError block in the middle of program
flow. The scope of OnError is that of the task withing which it is contained. It
only handlers errors that occur within that task.
