Major Fault - Out of Range Value

What does 20 mean?

This major fault (type 4, code 20) is generated when an expression overflows and the resulting value is out of range. This specifically applies to CompactLogix 5380, 5480, ControlLogix 5580, Compact GuardLogix 5380, and GuardLogix 5580 controllers. It indicates a critical calculation error that can impact program execution.

• An expression in a math operation overflows its data type capacity.
• The resulting value from an expression falls outside the valid range for its assigned variable.
• An array subscript value is too large or out of range, leading to an address error.

Click steps to track your progress.

1. 1

   Identify the specific faulted routine and instruction within the controller's Major Fault Data.

2. 2

   Inspect the logic of the identified routine and instruction for arithmetic operations or data manipulations that could generate an overflow or out-of-range value.

3. 3

   Monitor the real-time values of all input and intermediate tags involved in the problematic expression to verify they are within their expected operational limits.

4. 4

   Verify the data types assigned to the problematic tags and intermediate results to ensure they have sufficient range to prevent overflow.