Rockwell Automation AutoMax Enhanced Ladder Language Reference Manual - Manual (Page 305)

DĆ3
D.2 Using the PreĆDefined Error Handling Variables
Use the following Boolean variables to help you handle error conditions. Use error_eno
and no_error_log for output (read and write) parameters. You can use task_error as
either an input (read only) or output (read and write) parameter:
D task_error This variable is set true whenever an error is found. Monitor the bit to see if an
error occurs during execution and clear it by using the ladder logic. This bit is
set true even if errors are not being logged.
D error_eno Use this bit to determine the value ENO outputs will have if the instruction has
an error. The default value is false, which disables any instructions that are
connected to the ENO output, possibly making math expressions incomplete.
When you set error_eno true, you can continue the execution of the logic
connected to the ENO output even if the instruction block had an error.
This variable can be changed during ladder logic program execution.
D no_error_log Set this variable true to prevent errors from being entered into the program
error log or being seen by the rung monitor. Only one error is logged for each
instruction per program scan; however, you may want to prevent the errors
encountered on certain instructions from being entered into the error log.
The default state for the no_error_log is false. You can suppress error
messages for a group of rungs by changing this variable during program
execution. STOPĆALL errors and parameter limit errors for AR1, AR2, and ARC
instructions are still inserted into the error log when the no_error_log variable is
true.