Reason for FPU overflow error in AC500 PLC
Hello i am using the C code app in the Automation builder 1.0.
I am writing a function block in the C code app but when i download the program in the PLC (AC500 - PM592) my CPU goes to stop mode with the error pop up 'FPU overflow error'.
could you please let me know the reason and explanation of the error code?
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We can not find the error point of your program but, it seems there is a problem with type conversion or something else.
Because the FPU will raise the overflow exception if calculation overflows or if you attemp to sotre a value which is too large to fit into a destination point. (for example storing a large extended precision value into a single precision variable.)
Hope this helps you.
FPU Overflow exception is a built in safety mechanism for CPUs with floating point coprocessor (i.e. PM59x) to prevent unexpected corruption or warping of values. This can be due to the overflow (value is too big to fit into destination, i.e. LREAL being pushed into REAL address) or value being too small (negative exponent too big).
You could either login to the PLC and check the Call Stack when the exception is raised, or you could DISABLE FPU exception algother (if you are very sure that this would not jeapordize the safety of your process or machinery).