| 摘要 |
PURPOSE:To improve the accuracy of operations by selecting approximate expressions by desired constant terms and operating correction according to inputting of process variables. CONSTITUTION:The respective differential values of the coeffts. of conversion to volume at the prescribed temps. of liquid of various specific gravities and respective proportional constants are stored with a specific gravity value odi as a key code in an ROM15. A specific gravity value (o) is inputted as a process variable into an A/D converting part 11. With the output thereof as a key code, a CPU12 reads out the constant term of the coinciding approximate expression from the od table in the ROM15. When the value od does not coincide with the same, two sets of the constant terms wherein the od is an intermediate value are read out and are subjected to a linear interpolation operation, whereby the constant term conforming the od is calculated. With respect to liquid temp. as well, the coeff. K0 for conversion to volume is calculated. Thus the constant terms are determined according to the inputted od values and the approximate expressions to obtain desired specific gravity values are determined. |
