The output types are divided into: voltage output, open circuit output of set electrode, push-pull complementary output and long line drive output. In the form of mechanical installation of encoder classification 1. SHAFT TYPE: Shaft type can be divided into clamping flange type, synchronous flange type and servo installation type. 2. Sleeve Type: Sleeve type can be divided into half air type, full space type and large caliber type, etc. The principle of encoder can be divided into: photoelectric, magneto-electric and contact brush.