Extensometers govern the accuracy of the Roll Force Measurement System. Although similar in operating principal to a load cell, an extensometer is calibrated in strain (or stretch) instead of load. Actually, where maximum roll force may vary considerably from mill to mill, post strain remains within a range of 33 to 130 microinches per inch. extensometers are designed for optimum performance over this range. Installing extensometers on both the work and drive sides of the mill enables the user to achieve a balanced force at all times. With extensometers installed, the mill posts become an active part of the measuring system. The entire mill housing with the attached extensometer can be considered a "load cell". For additional system information, please refer to the G4 and RFS4 datasheets.