National Instruments ( NATI), a maker of process testing equipment and software for computers, said its second-quarter earnings rose 13.3%. The Austin, Texas-based company earned $17 million, or 21 cents a share, in the quarter, compared with $15 million, or 19 cents a share, a year ago. After adjustments, the company reported a profit of 25 cents a share. Analysts polled by Thomson First Call were expecting earnings of 19 cents a share in the most recent quarter. Second-quarter revenue rose 13.7% to $160.1 million, led by strong sales of software, PXI, modular instruments and distributed I/O products, as against analysts' estimate of $161 million. For the third quarter, the company expects to earn between 16 cents to 21 cents a share and between 21 cents to 26 cents a share after excluding stock-based compensation expense and impact of the amortization of acquisition-related intangibles. Analysts polled by Thomson First Call estimate earnings of 19 cents a share. The company has projected third-quarter revenue of $157 million to $164 million as against analysts' estimate of $163 million.