Testing electronic balance performance

Electronic balance is one of the routine laboratory instruments, which is a precision electronic instrument. Therefore, before using electronic balance, its properties need to be checked. So, what are the inspection methods?
　1、 Inspection of mechanical parts
　　(1) Switch inspection (whether it is too tight, too loose, or the eccentric shaft cannot rotate to the lowest point or exceeds the lowest point)
　　(2) Column inspection (verticality of column, level, base plate)
　　(3) Check the crossbeam of the electronic balance (whether the agate blade is worn, whether the sensing weight and balance weight have slipping, and whether the pointer is perpendicular to the crossbeam)
　　(4) Check the suspension system (whether the lifting ears are stuck, tilted, or wobbled, whether the dampers are stuck or wobbled in the inner and outer cylinders, and whether the weighing plate is tilted).
　　(5) Is there any jamming phenomenon in the encoder.
　2、 Inspection of optical system
　　(1) Is the light bulb not working, has insufficient brightness, or is it a continuous light.
　　(2) Is the light screen normal (no light, weak light, black red light or strip light)
　 (3) Whether the scale is normal (whether the scale is clear, invisible, tilted, or curved).
3、 Inspection of metrological performance
　　(1) Has the zero point of the empty scale changed.
　　(2) Is the empty scale sensitivity consistent with the full scale sensitivity.
　　(3) Compare the deviation of the balance using two full weights, exchange the two full weights, eliminate the weight difference, and calculate the magnitude of the deviation compared to the balance.
　　(4) Add the same small weight to each of the left and right plates, and compare the difference in sensitivity between the two plates, known as "bias sensitivity".