​Emergency treatment method for the confused code of electronic bench scale instrument

Emergency treatment method for the confused code of electronic bench scale instrument

     A. Structure and basic principle of electronic bench scale weighing instrument

Electronic scale weighing instrument is usually composed of a scale platform, a scale body, a display instrument and peripherals, among which the scale body is mainly composed of a weight sensor, a speed measuring sensor and a junction box. The basic principle is that the weight signal of the electronic bench scale weighing instrument is converted by the weighing sensor into the corresponding proportional electrical signal output, which is an analog signal. The analog signal is converted into digital signal after amplification, filtering and A/D conversion, and then displayed on the display screen after processing.

     B. classification of electronic bench scale weighing instruments

According to the type of signal source, electronic scale weighing instruments can be divided into two categories: analog weighing instruments and digital weighing instruments. The basic principle of the former is to change the resistance value of the resistance strain gauge by weight, and then convert the change into the corresponding electrical signal through the sensor. The latter is based on the traditional strain weighing sensor, combined with microprocessing technology, electronic technology, digital compensation technology, relying on the computer to calculate the weight and then display, storage, printing and transmission.

     C. Common faults and maintenance methods of electronic bench scale weighing instrument

There are many faults in electronic bench scale weighing instrument, and the cause is not limited to one. At the same time, even if the malfunction is the same, the cause may be different. The key to smooth troubleshooting is to find the fault location through the correct method.

     D. Common electronic bench scale weighing instrument failures include the following

       1  fault of external environment
       Vibration, change of power supply, lightning, wind and other external environment changes may be the cause of the unstable operation of electronic scale. Therefore, the electronic scale should be protected from starting up in bad weather as far as possible, and lightning protection and grounding protection should be strengthened.
       2  sensor failure
       In  the electronic bench scale, the weighing sensor is the core component, whose function is to convert gravity into electrical signals. If the weighing sensor fails, the weighing error will be caused.

     E.  The maintenance treatment measures for these situations are as follows
       1.  Electronic bench scale cannot be returned to zero
       First check whether the output signal of the sensor is within the standard value. If not, the adjustable resistance in the sensor can be adjusted; If the problem still cannot be solved, the sensor can be checked or replaced. If the sensor is normal, it should be an instrument fault.
       2.  The balance of electronic bench has large deviation or repeated variation
       The most likely cause is a small signal input range change. If the problem cannot be found by referring to the non-zero-back detection method, the power supply  and A/D circuit should be tested first, and then the output of the sensor should be tested or detect sensor faults through dynamic measurement: measure whether the voltage of S+ to                   earth and S- to earth is equal (0 error is the  best), if not equal, the sensor should be compensated; Instead, a resistor is placed between the sensor "E+ -s +" to bring the signal back to normal.
       3.  Mechanical failure of scale body
       Mechanical failure mainly has four kinds: one is the weighing body force deformation; Second, the scale body is supported by foreign bodies; Third, the limit device failure;  Four is the weight sensor support head fault. Mechanical parts due to long-term force friction and easy to damage, this kind of fault can be directly observed by the naked eye,              but also through the balance body whether the shaking to judge and effectively solve.