A detailed description GWB-200JA type extensometer calibrator is a purely mechanical precision micrometer displacement instruments. Verification procedures based JJG762-92 extensometer requirements, specifically for all types of extensometer calibration, also widely used test and the corresponding displacement sensor dial, dial gauge calibration. Structural features and a reading mode, the instrument consists of precision measuring differential probe and frame composition. The calibrator is a modular design. The precision differential probe and arm in a variety of ways or a combination of location, but with a longer post attachments with cylindrical, plates, blades and other forms of separation of the sample can be easily carried in a variety of standard models extensometer measurement calibration. Users can also test their own special needs, configure a dedicated accessories for precision micro deformation metering. 2, precision differential probe volume by sliding rod measuring rod sleeve, inner tube readings, readings of the outer cylinder and high-precision threaded pay components. Its maximum range of 25 mm; minimum scale (vernier indexing) 0.0002㎜; 0.002㎜ indexing rotation of the outer cylinder. Displacement reading is: L = (a + 0.001b + 0.0001c) - (a0 + 0.001b0 + 0.001c0) wherein: a- inner cylinder mm scribing reading b- reading c- outer cylindrical groove vernier reading reticle a0 b0 c0 for the first reading of the corresponding displacement precision differential cylinder Second, the technical indicators of a precision measurement range of the extensometer gauge length Lmax 500 mm 2, the measuring arm mount installation aperture φ10; φ28 3, differential probe readings inner tube 0.5 mm axial scale / grid 4, differential probe readings inner tube vernier 0.0002㎜ / div 5, differential probe readings outer cylinder circumference scale 0.002㎜ / div 6, high-precision differential probe calibrator accuracy index showing error : Within the range of 0.5 mm 0.5 mm above ≤0.5μm absolute error range ≤0.10% relative error by point of reference: JJF1096-2002 extensometer calibration calibration specification ISO9513: 1999 uniaxial testing of metallic materials extensometer extensometer calibration JJG762-1992 test procedures can be carried out 0.5 extensometer calibration