Fast and accurate sensor test method

2019/07/10

Fast and accurate sensor test method shared by the Laboratory Balance Supplier.

When the electronic scale cannot be weighed, such as the constant reminder of err-6 on the screen, there are still two possibilities, one is the sensor damage, the other is the AD circuit damage. How to quickly and accurately judge the sensor fault or AD circuit fault can greatly improve the maintenance efficiency. The easiest way to find fault components is the substitution method, but whether it is to replace the AD chip or sensor, it will take a lot of time. Now a convenient test method is briefly introduced.

Generally, multimeter is used to detect the input and output resistance of the sensor. However, since the damage of most sensors does not affect the input and output resistance, this method does not work well.

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Now another test method is introduced, which is power on test. If it is a single sensor before it is installed, it only needs to apply a dc voltage between E+E-, and the simplest is to connect a battery. If the sensor is detected in the whole machine, only the S+S- wires need to be removed from the circuit. In either case, first make sure there is a power supply to supply the battery to E+E-, and then connect S+S- to the voltage level of the multimeter, depending on the situation. For example, if the excitation voltage of the sensor is 5V and the sensitivity is 2mV/V, then in the optimal case, the zero output is 0mV and the full load output is 10mV, so the 20mV gear is ok. Then we start to test two values. One is zero output, which should be 0mV. Of course, a little deviation can be used. After loading, the output voltage is tested. If the output voltage does not change after loading, or is too far from the theoretical value, the sensor cannot be used. Theoretical sensor output voltage = excitation voltage X sensitivity X (current load/sensor range) + zero output.

This live test method can quickly determine the sensor fault, so as to determine whether it is the sensor problem or the AD circuit problem, and improve the efficiency of maintenance.

That's all for the sharing, thanks for your reading, and we also supply load cell lab scales precision balances  for sale, if you have any demand for our products, just feel free to contact us.