Overflow is an error condition in computing that occurs when the result of an arithmetic operation is a number too large to be stored in the allocated memory space or variable type. Every variable type in programming (such as a 16-bit integer or a 32-bit floating-point number) has a finite range of values it can represent. If a calculation produces a value that exceeds the maximum limit of this range, an overflow occurs.
For example, a signed 16-bit integer can hold values up to 32,767. If a variable holding the value 32,767 has 1 added to it, the result cannot be stored correctly. What happens next depends on the system; often, the value will "wrap around" to the minimum negative number (-32,768), leading to unexpected and incorrect program behavior.
In the context of instrument control, programmers must be aware of potential overflows when processing measurement data. For instance, if a series of readings are being summed to calculate an average or total power, the variable holding the sum must be large enough to accommodate the final result without exceeding its maximum capacity. Neglecting this can result in significant errors in data logging or control logic.