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Identify the exact line in the macro program where the alarm occurred by checking the program position on the control display.

Review the mathematical operations on that line and trace back the values of all variables involved using MDI mode to check their current values (#500-#999 range).

Add intermediate calculation steps to break down large calculations, or implement range checking with IF statements before performing operations (e.g., IF[#100 LT 10000] THEN #110=#100*#100).

Test the modified macro with known safe values first, then gradually increase to production values while monitoring variable values.

Locate the division, SQRT, or trigonometric function in the macro code at the alarm position.

Check if denominator variables or function arguments could be zero or negative by reviewing the logic flow and initial variable assignments.

Add conditional checks before mathematical operations (e.g., IF[#102 NE 0] THEN #103=#101/#102 ELSE #103=0 for division operations).

Always initialize macro variables before use; uninitialized variables default to <null> which can cause unpredictable behavior.

Implement error handling using GOTO statements to branch to alarm or default value assignments when invalid conditions are detected.

Review the assignment statement at the alarm line for proper syntax (format should be #i=#j or #i=<expression>).

Verify that the right-hand side expression produces a valid numeric result within range, checking for exponential notation results (e.g., 1.5E+10).

Check parameter 6036 (macro variable overflow detection) setting if available on your control; setting to 0 may suppress some overflow detection but does not fix root cause.

Changing parameter 6036 masks the problem rather than solving it; use only for temporary diagnostics.

Use ROUND, FIX, or FUP functions to control decimal precision and limit variable magnitude before assignment (e.g., #110=ROUND[#100*#101]).