Drive Programming Nesting Count Error

What does E44 mean?

This fault occurs when the Drive Programming logic contains subroutines, if-statements, or for-next loops that are nested more than eight layers deep. This exceeds the inverter's processing capability for program complexity, causing a trip to prevent runtime errors and ensure system stability.

• Complex Drive Programming (DP) logic exceeding the inverter's maximum nesting depth for control structures (e.g., IF/THEN/ELSE, FOR/NEXT, GOSUB statements).
• Poorly structured program flow leading to unintended recursive calls or excessive nesting of subroutines.
• Copy-pasting large blocks of code without understanding the cumulative nesting depth of the combined logic.
• Logical error in loop conditions causing infinite or excessively deep iterations.
• Using programming constructs that, although seemingly simple, create hidden deep nesting levels internally.

Click steps to track your progress.

1. 1

   1. Carefully review the Drive Programming (DP) code to identify all nested control structures (IF, FOR, GOSUB) and count their depth.

2. 2

   2. Refactor the DP program logic to reduce nesting depth; break down complex routines into simpler, flatter sequences.

3. 3

   3. Consider using flags, state machines, or global variables instead of deep nesting for sequential operations or complex conditional logic.

4. 4

   4. Consolidate redundant code blocks or use simpler conditional statements where possible to minimize structure complexity.

5. 5

   5. If a deep nesting structure is truly unavoidable for the application, consider if a more powerful controller (e.g., PLC) is required instead of relying solely on the inverter's built-in DP.