1.工作原理英国 NPL 最近研制了一台装有径向光栅的测角仪作为角度基准。理论上,由于已知角可通过对360°作适当的局部分度来产生,故具有确定角度的制件不需要主基准。但实际上,局部分度困难而费时。因此,必须建立国家角度主基准,使工业中的参考角度标准检定,能够 1. Working Principle British NPL recently developed a goniometer equipped with a radial grating as an angle reference. In theory, a workpiece with a defined angle does not require a master datum because the known angle can be generated by proper local indexing of 360 °. In fact, however, local indexing is difficult and time-consuming. Therefore, it is necessary to establish a national benchmark for benchmarking so that the reference standard in industry can be verified