Electronic scales are digitally displayed weight measuring instruments with electronic devices. It is composed of: load cell, operational amplifier, A/D conversion integrated circuit, intelligent single-chip, display driver and display circuit, keyboard circuit, multi-function interface circuit, AC/DC/charge/storage/regulator circuit. The phenomena and root causes of various failures are bizarre.
1 does not return to zero (does not return to zero, do not weigh)
a Check if the sensor output signal value is within the standard. (A/D total code/use inner code range/base code range)
b is not within the standard. Please refer to item 10 for compensation.
cIf it cannot be compensated, check the sensor for bad. (Please check according to item 8)
d Follow the instruction manual to do weight correction.
2 The weight is not allowed. a. Is the observed internal code value stable? Is there any friction in the sensor? Are the regulated power supply stable? Is the op amp circuit normal? Is there a foreign object on the circuit board of the A/D circuit? Feedback resistor/capacitor/filter? Whether the capacitor is bad or leaks.
b Check if the sensor output signal value is within the standard.
c is not within the standard, please refer to item 10 for compensation.
d Use weights to test if the scales on the weighing pan are average. (if not average, please refer to the ninth item for grinding scales)
e Follow the instruction manual to do weight correction.
3 can not boot a Please first determine the non-fuse, power switch, power cord and voltage switch caused by the problem.
b Check whether the transformer has AC110/220 input and AC18V output.
cPlease remove the battery and turn it on with AC power to see if it is caused by a low battery voltage. (Measure the battery voltage, if it is higher than 6V, if it is lower, please charge it. If it is lower than 5.5V, please replace the battery when the battery is fully discharged soon after it is fully charged).
4 Display failure a Connect the normal LCD pin to the LCD of the maintenance scale by hand, and then turn on the LCD to see whether the same LCD does not have the same good condition. If not, you can conclude that the LCD is bad.
b Check the CPU pin for oxidation, cold soldering or short circuit.
CLP pins and holes are oxidized, cold soldered, or shorted.
d Check for open circuit between the CPU and LCD.
5 Bad key a Please update the K/B test first. If the new K/B function is normal, it can be judged as bad K/B.
b Measure whether the line between K/B and CPU is open or cold.
c Check the K/B leg for poor contact.
d Measure whether the diodes on the K/B and CPU circuits are short-circuited or open circuited.
6 can not be fully loaded?
a Check if the sensor output signal value is within the standard.
b is not within the standard. Please refer to item 10 for compensation.
cIf it cannot be compensated, check the sensor for bad. (Please check according to the eighth item)
d If there is any instability or compensation after compensation, replace the sensor.
e Check that there is interference inside the radio or protection device.
f The battery voltage is above 6V.
g Replace the L/C test due to a bad sensor.
7 The battery cannot be stored a. Please confirm that it is caused by a problem other than the fuse, power switch, power cord and voltage switch.
b Check whether the transformer has AC110/220 input and AC18V output.
c. Remove the battery from the board and remove the PIN. Measure the charging voltage of the board to be 7.2V. If not, check the power supply related circuits.
d Check the machine board, and whether the diode near the PIN input terminal of the transformer is normal.
e Replace the battery.
8 sensor failure to determine a static method: use three-meter meter Ohm, respectively, measuring the sensor E + S +, S-(or E-pair S +, S- can be) resistance is the same, in general If the error is more than 0.5Ω, it needs to be compensated. If the error is too large (more than 2Ω), it is recommended to replace L/C.
b dynamic method: the correct connection of the sensor wiring back to the motherboard, the use of digital electric meter (more than four and a half or more) of the DCV file, measuring S + ground and S-to-ground voltage is equal (preferably 0 Errors) Sensor compensation if not equal.
9-corner coupling adjustment (single sensor)
a First weight correction.
b Measure the display value at the four corners of the weighing pan with a full load of 1/3 of the weight.
c Press the zero side of the lowest value of the scale in the 1 to 4 corners of the file. (When grinding the scale for the first time, test the force with a small force test to avoid damage to the sensor.)
d Repeat 2~3 actions until the error of the four corners of the weighing pan with the center as the reference is within ±1 hop, then do the weight correction.
e If the error value of the pan angle is too large and the scale is too large after the scale has been scaled, it means that the sensor is faulty or the method of grinding scale is wrong.
When measuring the f-scale, it is necessary to pay attention to the specifications of the sensor. The lighter the full-load weight, the lighter the grinding force.
10 Sensor Compensation a Sensor output signal is too high. Add a resistor (50K~2.2MΩ depending on the situation) to make the signal between the sensor's "E+S-" value to the normal range. (The lower the resistance value, the greater the output signal of the sensor. low).
b Sensor output signal is too low or -ERR Please add a resistor (50k~2.2MΩ for use) to make the signal value within the range of "E+~S+" of the sensor to normal range (lower resistance value = higher sensor output signal ).
Nezha V
DUDU NEW ENERGY AUTOMOBILE COMPANY , https://www.duduelectriccar.com